The story
- Latin · borrowed fromdēclīnātus
- English todaydeclinate
The adjective is first attested in 1820; borrowed from Latin dēclīnātus, perfect passive participle of dēclīnō (“to bend down”), see -ate (adjective-forming suffix) and -ate (verb-forming suffix).
Etymology from Wiktionary, CC BY-SA 4.0.