annul (v.)

• abate
• abolish
• abrogate
• abstract
• annihilate
• buffer
• cancel
• counteract
• counterbalance
• countercheck
• countermand
• delete
• discharge
• dissolve
• divorce
• efface
• eliminate
• expunge
• extinguish
• frustrate
• invalidate
• negate
• negative
• neutralize
• nullify
• obliterate
• offset
• outweigh
• overbalance
• override
• overrule
• part
• quash
• recall
• recant
• redress
• remove
• renege
• repeal
• rescind
• retract
• reverse
• revoke
• separate
• stultify
• suspend
• thwart
• undo
• vacate
• vitiate
• void
• waive
• withdraw