משלי כה:יט פירוש: רש״י

a broken tooth Heb. רעה, broken.

unsteady Heb. מועדת, as in (Ps. 18:37): “and my ankles have not slipped (מעדו).”

trust in a traitor He disappoints him on the day of his trouble like a broken tooth and an unsteady [foot].