to make something no longer visible: to spoil how it looks, ruin it away to nothing, or (of the thing itself) fade from sight
This verb is built from the ordinary Greek word for appearing or coming into view (φαίνω) with a negative prefix in front of it, so its literal force is close to "to un-appear." Everything else follows from that. Whatever takes a thing out of sight can be described with this word: a cloud covering the sun, ash smeared on a face, mice eating through stored cloth, a city leveled, a mist burning off in the morning.
That is why the same word can sound gentle in one place and terrible in another. In the Sermon on the Mount it covers both a face made unrecognizable and treasure eaten away in a storeroom. In Paul's sermon at Antioch it is a threat of being wiped out. In James it is only a morning mist thinning into nothing. The idea holding all of that together is not violence but disappearance, which is what marks this word off from the blunter Greek verbs for destroying, such as ἀπολλύω.
Three of its five appearances in the New Testament play the word against its positive twin. The hypocrites in Matthew 6:16 make their faces unseen precisely so that they will be seen, and the mist in James 4:14 appears for a moment and then un-appears. In Greek the pairing is impossible to miss, and in English it is almost impossible to keep.
Nuances
Whether the hypocrites of Matthew 6:16 spoiled the appearance of their faces (leaving them unwashed, ash-strewn and haggard) or covered them from view with a veil.
- majorityThey made their faces unsightly: unwashed, ash-strewn, deliberately haggard, so that the fact of fasting would be advertised. Jesus' counter-command to wash and anoint the head is then simply ordinary daily grooming.; W. D. Davies and Dale C. Allison, A Critical and Exegetical Commentary on the Gospel According to Saint Matthew (ICC), vol. 1, p. 617; R. T. France, The Gospel of Matthew (NICNT), p. 255; Donald A. Hagner, Matthew 1-13 (WBC 33A), p. 154; Craig S. Keener, A Commentary on the Gospel of Matthew, pp. 216-18; BDAG, s.v. ἀφανίζω, sense 1 (render unsightly, disfigure)
- minorityThe verse describes hiding the face from view, and so belongs with the sense of causing something to disappear by concealing it.; Johannes P. Louw and Eugene A. Nida, Greek-English Lexicon of the New Testament Based on Semantic Domains, 2nd ed., §24.28; John Gill, An Exposition of the New Testament, on Matthew 6:16
Whether ἀφανίσθητε in the Habakkuk 1:5 quotation at Acts 13:41 threatens destruction or, following the Hebrew text's doubled תמה, means something closer to being struck dumb with astonishment.
- majorityIt carries the destructive force that dominates the verb in the Septuagint: perish, be destroyed, be wiped out. The Greek rendering turns Habakkuk's doubled expression of astonishment into an actual threat of judgment, which is what Paul's argument requires.; C. K. Barrett, The Acts of the Apostles (ICC), vol. 1, on 13:41; F. F. Bruce, The Book of Acts, rev. ed. (NICNT), on 13:41; Joseph A. Fitzmyer, The Acts of the Apostles (Anchor Yale Bible 31), on 13:41; Darrell L. Bock, Acts (BECNT), on 13:41; Eckhard J. Schnabel, Acts (ZECNT), on 13:41; Takamitsu Muraoka, A Greek-English Lexicon of the Septuagint (Louvain: Peeters, 2009), s.v. ἀφανίζω
- minorityIt should be softened toward astonishment or stupefaction, in line with the Hebrew of Habakkuk 1:5.; J. F. Schleusner, Novus Thesaurus Philologico-Criticus (Leipzig, 1820-21), s.v. ἀφανίζω; Albert Barnes, Notes on the New Testament: Acts, on 13:41