infect: [14] Latin inficere originally meant ‘put in’ – it was a compound verb formed from the prefix in- and facere ‘put, do’ (source of English fact, fashion, etc). Its earliest specialized extension was ‘dip in’, which was applied specifically to the dipping of cloth into dye. From this it moved on to ‘stain’, and then it was a short step to ‘taint, spoil’. ‘Affect with disease’ was a post-Latin development. English acquired the word via the Latin past participial stem infect-. => fact, factory, fashion, perfect
