'nonfloral' originates from the negating prefix 'non-' (from Latin 'non', meaning 'not') combined with the adjective 'floral' (from Latin 'floralis', from 'flos, floris', meaning 'flower').

'floral' entered English via Old French/Middle English from Latin 'floralis'; 'nonfloral' is a modern English compound formed by adding the negating prefix 'non-' to 'floral'.

Initially the elements meant 'not' and 'related to flowers' respectively; the compound's meaning has remained the straightforward 'not relating to or characterized by flowers' in modern usage.