1. Act in opposition to
   - antagonize, antagonise [Brit] 
2. Oppose or check by a counteraction
   - countercheck 
3. Oppose and mitigate the effects of by contrary actions
   "This will counteract the foolish actions of my colleagues"
   - countervail, neutralize, counterbalance, neutralise [Brit] 
4. Destroy property or hinder normal operations
   - sabotage, undermine, countermine, subvert, weaken

Derived forms: counteracted, counteracting, counteracts

See also: counteraction, counteractive

Type of: act, cancel, check, contain, control, curb, disobey, hold, hold in, moderate, move, offset, set off

• long tom
• long ton
• long trousers
• long underwear
• long wave
• long weekend
• long whist
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• long-billed marsh wren
• long-bodied
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• long-chain molecule
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• long-distance call
• long-distance runner
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• long-eared owl
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• long-fin tunny