'animal-unfriendly' originates from English, being a compound of the noun 'animal' and the adjective 'unfriendly'. 'Animal' ultimately derives from Latin 'animalis' (from 'anima' meaning 'breath, life, soul'), while 'unfriendly' is formed from the negative prefix 'un-' plus 'friendly' (Old English elements related to 'frēond' meaning 'friend').

'Animal' came into English via Latin 'animalis' and Old French 'animal' before reaching Middle English as 'animal'. 'Friendly' traces back to Old English 'freondlic' (friend-like), with the negative prefix 'un-' attached in Middle English to form 'unfriendly'. The hyphenated compound 'animal-unfriendly' is a more recent English formation used to describe actions or policies harmful to animals.

Individually, 'animal' originally referred to living creatures (from 'life, soul') and 'unfriendly' meant 'not friendly'; combined in modern usage they evolved to denote actions, practices, or attitudes that are harmful or lacking in consideration toward animals.