"pertaining to or of the nature of retaliation," 1783; see retaliate + -ory. Alternative retaliative is attested from 1819 but seems more to mean "vindictive, revengeful."
Entries linking to retaliatory
retaliate v.
"requite, repay, or return in kind," 1610s, from Latin retaliatus, past participle of retaliare "pay back in kind," from re- "back" (see re-) + Latin talio "exaction of payment in kind," from or influenced by talis "suchlike" (see that). Originally of kindness, civility, etc., but by 1630s of injury, ill-treatment, etc. (now the usual sense). Intransitive sense is from 1650s. Related: Retaliated; retaliating.
-ory
adjective and noun suffix, "having to do with, characterized by, tending to, place for," from Middle English -orie, from Old North French -ory, -orie (Old French -oir, -oire), from Latin -orius, -oria, -orium.
Latin adjectives in -orius, according to "An Etymological Dictionary of the French Language," tended to "indicate a quality proper to the action accomplished by the agent; as oratorius from orator; laudatorius from laudator. The neuter of these adjectives was early employed as a substantive, and usually denoted the place of residence of the agent or the instrument that he uses; as praetorium from praetor; dormitorium from dormitor; auditorium, dolatorium.
"These newer words, already frequent under the Empire, became exceedingly numerous at a later time, especially in ecclesiastical and scholastic Latin; as purgatorium, refectorium, laboratorium, observatorium, &c." [transl. G.W. Kitchin, Oxford, 1878]