to fill someone with food until they have had enough; to eat one's fill, be satisfied
This verb means to fill a person with food until the hunger is completely met, to eat one's fill. It began as the word for feeding animals: the related noun means "grass" or "fodder," so the picture was originally of livestock grazing to the full. By the time of the New Testament it had lost that barnyard flavor entirely and was used freely of people being fully fed and satisfied, with no hint of anything demeaning.
This is the word behind the feeding miracles, where the crowds "ate and were filled." Its range runs from a hungry son longing to stuff his stomach with pigs' pods, to a beggar wishing to be fed with the crumbs off a rich man's table, all the way to the scavenging birds "gorged" on flesh in Revelation. Underneath every use lies one simple idea: a hunger met all the way, nothing left wanting.
Jesus takes that concrete, bodily picture and lifts it higher: "Blessed are those who hunger and thirst for righteousness, for they shall be filled." The same strong word for a full stomach now carries a promise that a deep spiritual hunger will be met just as completely. It echoes the older Hebrew language of being satisfied (שָׂבַע), and it stands close to other Greek words for filling and satisfying such as κορέννυμι and ἐμπίμπλημι.