'snub-nosed' is a compound of 'snub' + 'nose'. 'snub' in English goes back to Middle English and is probably related to Middle Dutch 'snubben' or Old Norse 'snubba' (both with senses related to cutting short or striking), while 'nose' originates from Old English 'nosu'.

'snub' developed as an adjective meaning 'short, turned up, or blunt' in early modern English; this adjective combined with 'nose' to form the descriptive compound 'snub-nosed' in later English usage.

Originally, 'snub' had senses including 'to check or rebuke' (verb) and the physical sense 'short or abruptly cut' (adjective); over time the compound 'snub-nosed' came to be used specifically for a short, flattened, or upturned nose.