[f. UNDO v.] Ruinous, destructive.
1654. Tuckney, Death Disarmed, 33. It is an undoing gain to break their arm by catching at a feather.
1681. Flavel, Meth. Grace, xvi. 305. Little do such men know how … they put an undoing cheat upon their own souls for ever.
1793. Anna Seward, Lett. (1811), III. 292. The present fashion of head-dress … has an undoing influence upon youth and beauty.
