critter (n.)

c. 1300, "anything created," hence "a thing" in general, animate or not, but most commonly "a living being," from Old French creature "created being; all creation" (Modern French créature), from Late Latin creatura "a thing created; the creation; a creature," from creatus, past participle of Latin creare "to make, bring forth, produce, beget," from PIE root *ker- (2) "to grow."

Used of humans in limited cases, in contempt, commiseration, endearment. Meaning "person who owes his rise and fortune to another" is from 1580s. Meaning "anything that ministers to man's comforts" (1610s) is after I Timothy iv.4 ("Every creature of God is good") and led to the jocular use of creature for "whiskey, intoxicating drink" (1630s). Creature-comforts "material comforts" (food, clothing) is from 1650s. Related: Creatural; creaturely.