to be joined firmly to someone or something, as if glued on: to cling, unite, or attach oneself closely
TranslatabilityApproximateCertaintySettled
The picture behind this word is literally glue. It comes from the noun for glue or cement, and its base idea is two things bonded so tightly they act as one. In the New Testament it almost always appears in a form that means you do it to yourself: you fasten yourself onto a person, a group, or a thing, rather than being stuck there against your will.
From that one image the word fans out across a wide range, and the shade is set by what a person attaches to:
dust that sticks to the sole of a sandal
a hungry man who hires himself out to a landowner
a newcomer trying to be accepted into a wary circle
a husband and wife who become one flesh, or a believer who becomes one spirit with the Lord
a person who holds fast to what is good
Because the same verb covers a beggar latching onto an employer and a marriage becoming one flesh, the intensity is never in the word by itself. It comes from the relationship in view. A close Greek relative, the strengthened compound προσκολλάω, does the marriage-union work in some passages, and in the Hebrew scriptures the matching word is דָּבַק, which likewise runs from a man cleaving to his wife to Israel clinging to God.
Nuances
1ato stick to, adhere to (physically)
TranslatabilityDirect
Luk 10:11
1bto attach oneself to a person or group; to associate with, keep company with, join
adds the reflexive sense of fastening oneself on by choice, as when a man hires himself out or holds fast to what is goodLuk 15:15Rom 12:9
Both
both name a tight, sticking attachmentLuk 10:11
Only cling
English "cling" can suggest neediness or desperation, a coloring the Greek does not require
“cleave”
Comparison data is not available for this English gloss yet.
“unite”
Comparison data is not available for this English gloss yet.
“keep company with”
Comparison data is not available for this English gloss yet.
How kollaō differs from similar Greek words
προσκολλάωthe strengthened compound of this verb, to glue firmly onto; it does the marriage-union work (a man joined to his wife) where the plain verb is used more loosely for any close attachment
Ranges far beyond marriage to attachment of every kind: dust clinging to the feet as a sign against a town (Luke 10:11), a hungry man hiring himself out to a local landowner (Luke 15:15), Philip running to attach himself to the chariot (Acts 8:29), and Paul trying to join the wary disciples (Acts 9:26).Luk 10:11Luk 15:15Act 8:29Act 9:26
Names close human company where people keep or refuse each other's fellowship: no one dared associate with the apostles (Acts 5:13), and a devout Jew was not to keep company with a foreigner (Acts 10:28).Act 5:13Act 10:28
Carries the deepest union imagery, whether holy or shameful: the person who is united to the Lord becomes one spirit with him (1 Corinthians 6:17), while the one united to a prostitute becomes one body with her (1 Corinthians 6:16).1Co 6:171Co 6:16
Stretches to loyal devotion and even to a heap piling up: holding fast to what is good (Romans 12:9), and a city's sins stacking up all the way to heaven (Revelation 18:5).Rom 12:9Rev 18:5
Both
Both render the same line of the marriage saying, that a husband shall be joined to his wife: Matthew's Gospel uses the plain verb (Matthew 19:5) while Mark and Paul reach for the compound (Mark 10:7;Ephesians 5:31), and both picture a permanent bonding of the two into one.Mat 19:5Mrk 10:7
Appears only in the marriage-union saying, where the prefix sharpens the sense of being firmly bonded toward one's wife: a man leaves his parents and is joined to his wife (Mark 10:7;Ephesians 5:31).Mrk 10:7Eph 5:31
ἀντέχωto hold firmly to and stay loyal to, of choosing one thing and keeping to it, where this verb pictures bonding or sticking fast
reaches into forced loyalty: a devotion to one party that by its nature rejects a rival, holding to one master while despising the otherMat 6:24Luk 16:13
keeps a firm grip on a fixed body of teaching, staying true to a trustworthy messageTit 1:9
can mean to hold someone up and support them, active care for the weak rather than mere attachment to a thing1Th 5:14
kollaō in the other biblical languages
דָּבַקHebrew“to cleave”the Hebrew twin, to cling or cleave, running the same range from a husband cleaving to his wife to Israel clinging to God; the Greek Old Testament regularly renders it with this verb
Names the act of attaching oneself socially to a person or group, joining their company: outsiders dared not associate with the apostles, Saul tried to join the disciples, a Jew was not to keep company with a Gentile.Act 5:13Act 9:26Act 10:28
Used for hiring oneself out or attaching oneself to a master for work, as the prodigal son fastened himself to a citizen of the far country to feed pigs.Luk 15:15
Both
Both name the one-flesh union of marriage: a man leaves his parents and is joined to his wife, the Hebrew word in the creation account and the Greek word in Jesus' quotation of it.Gen 2:24Mat 19:5
Both can mean clinging in moral devotion: holding fast to what is good, holding fast to the LORD.Rom 12:9Deu 10:20
Both name the deliberate joining of one person to another that fuses them into a single bond, whether to the Lord or, in warning, to a prostitute.1Co 6:161Co 6:17Gen 34:3
Carries a strong covenant register: clinging to the LORD himself in faithful loyalty, the standing summons of the law and the praise of Israel's best kings.Deu 11:22Deu 30:202Ki 18:6
Pictures a body part stuck fast in distress: the tongue glued to the roof of the mouth, bones clinging to the skin.Job 29:10Psa 137:6Psa 102:5
Describes pressing close in pursuit, staying right on an enemy's heels until they are overtaken in battle.Jdg 20:421Sa 31:22Sa 1:6
What scholars say about kollaō
The verb derives from κόλλα (glue) and denotes a firm bonding; in the New Testament it occurs almost exclusively in the passive with reflexive force, hence "join oneself to, cling to, associate with." BDAG groups the usage under joining/uniting (of marriage and sexual union in Matt 19:5 and 1 Cor 6:16, and of union with the Lord in 1 Cor 6:17), associating oneself with persons (Luke 15:15;Acts 5:13; 8:29; 9:26; 10:28; 17:34), and clinging to things, whether the dust of Luke 10:11 or the good of Rom 12:9, with the accumulation image of Rev 18:5 treated as a figurative extension. Matt 19:5 and 1 Cor 6:16 draw on Gen 2:24, where the Greek Old Testament renders Hebrew דָּבַק with this verb and its compound προσκολλάω, tying the New Testament union language to the older cleaving idiom.
Sources
BDAG, s.v. κολλάωlexicon
Louw & Nida, Greek-English Lexicon of the New Testament Based on Semantic Domains, §34.19, §18.6lexicon