Warfare between forces unequal in size, composition, or means; specifically warfare in which a smaller or ostensibly inferior force uses unexpected, unconventional tactics to its advantage in combating a larger or apparently superior adversary.
Origin
1990s; earliest use found in Press Association.
Definition of asymmetric warfare in US English:
asymmetric warfare
noun
Warfare between forces unequal in size, composition, or means; specifically warfare in which a smaller or ostensibly inferior force uses unexpected, unconventional tactics to its advantage in combating a larger or apparently superior adversary.