καταπηγνύναι
From LSJ
To χάρις ὑμῖν οὕτω τίθησιν κτλ. → Thus he writes joy to you all, etc. (Cramer's Catena on 1 Thessalonians 1.1)
Greek > English (Woodhouse Verbs Reversed)
(see also καταπήγνυμι): fix, drive into the ground, fix in the ground, plant firmly