'allergy-like' is formed by combining 'allergy' (originating in modern medical terminology from Greek elements) with the English suffix '-like' (from Old English 'lic', meaning 'having the form of').

'allergy' originates from the early 20th-century medical coinage (German/English) based on Greek 'allos' + 'ergon' (often rendered as 'allergia' in New Latin/German 'Allergie'), and '-like' changed from Old English word 'lic' (also seen as 'lich'/'liche' in Middle English) and eventually became the Modern English adjectival suffix '-like'.

The Greek-based coinage initially described an 'altered' or 'different' reaction; over time 'allergy' came to denote an immune hypersensitivity. The compound 'allergy-like' now means 'resembling or producing symptoms like an allergy'.