'flower-obsessed' is a modern English compound formed from 'flower' + 'obsessed'. 'flower' comes from Old French 'flor' and Latin 'flos, floris', where 'flos' meant 'flower'; 'obsessed' derives from Latin 'obsessus', past participle of 'obsidere', where 'ob-' meant 'against' or 'toward' and 'sedere' meant 'to sit'.

'flower' came into Middle English via Old French 'flor' from Latin 'flos', eventually becoming the modern English 'flower'; 'obsess' entered English from Latin 'obsessus' (via Late Latin), producing the past-participle-derived adjective 'obsessed', and the two elements were later combined in modern English to form compounds like 'flower-obsessed'.

Individually, 'flower' originally referred simply to the bloom or blossom ('flower'), and 'obsessed' originally denoted being besieged or occupied (by an idea); over time the compound 'flower-obsessed' came to mean 'excessively interested in flowers' rather than a literal sense of being 'besieged by flowers'.