SYN: Brat, scamp, devil, demon.
ANT: Cherub, angel.
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KEY: Impact.
SYN: Contact, application, impression, collision.
ANT: Isolation, separation, interval, removal, avoidance, non-contact, shave.
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KEY: Impair.
SYN: Deteriorate, injure, reduce, damage, enfeeble, vitiate, diminish, lessen.
ANT: Enhance, improve, augment, repair.