Hypallage (ὑπαλλαγή exchange) is a change in the relation of words by which a word, instead of agreeing with the case it logically qualifies, is made to agree grammatically with another case. Hypallage is almost always confined to poetry.
ἐμὰ κήδεα θῡμοῦ
the troubles of my spirit ξ 197, νεῖκος ἀνδρῶν ξύναιμον kindred strife of men for strife of kindred men Ant. 794. Here the adjective virtually agrees with the rest of the phrase taken as a compound.