Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
defuse, diffuse (vv.)
These near-homophones (pronounced dee-FYOOZ and di-FYOOZ, with only the unstressed syllables differing) are usually distinguished by context, but to choose the wrong spelling can be inadvertently funny, because the usual meanings when context is not definitive are almost directly contradictory: to defuse a tense argument is to render it less explosive and hence harmless, whereas to diffuse such an argument is to spread it around even further and thus perhaps make it worse. (The adjective diffuse is not homophonous with these verbs: it is pronounced di-FYOOS.)
