Albert Barnes Commentary Lamentations 2:5

"The Lord is become as an enemy, he hath swallowed up Israel; He hath swallowed up all her palaces, he hath destroyed his strongholds; And he hath multiplied in the daughter of Judah mourning and lamentation." — Lamentations 2:5 (ASV)

Literally, אדני 'ădonāy has become “as an enemy.”