Liddell-Scott-Jones

πιαίνω (piainō) to fatten ^G:V

πιαίνω,

future πιᾰνῶ [Refs 4th c.BC+]: aorist ἐπίᾱνα [Refs 5th c.BC+]:—passive, future πιανθήσομαι [LXX]: aorist ἐπιάνθην [Refs 6th c.BC+]; but aorist infinitive συμ-πιασθῆναι [Refs 5th c.BC+]perfect πεπίασμαι (κατα-) [Refs 5th c.BC+]: (πίων): fatten, τὸ σῶμα [Refs 5th c.BC+]; [τὰς ὗς] [Refs 4th c.BC+]; π. χθόνα enrich the soil, of a dead man, [Refs 4th c.BC+]; σώμασι πίαναν καπνόν, of bodies being burnt, [Refs 5th c.BC+] [same place]:—passive, to be or become fat, [Refs 7th c.BC+]

__II metaphorically,
__II.1 increase, enlarge, πλοῦτον [Refs 5th c.BC+]; μυχοὺς πόλεως [Refs 6th c.BC+]
__II.2 make wanton, ἀλλ᾽ ἦ σ᾽ ἐπίανέν τις ἄπτερος φάτι; [Refs 4th c.BC+]:— passive, wax fat and wanton, πρᾶσσε, πιαίνου [Refs 4th c.BC+]; ἔχθεσιν πιαίνεσθαι batten on quarrels, [Refs 5th c.BC+]; φθόνῳ π. [Refs 5th c.BC+]
__II.3 cherish, cheer, ἵππον.. π. ὁ τοῦ δεσπότου ὀφθαλμός [Refs 4th c.BC+]; μέλος[Refs 6th c.AD+] —Rare in Prose.

_{LSJ Scripture Refs: LXX.Ps.64.12*}