[nq:1]Detriment is one of those words which looks like an antonym but is not. Someone on the web, I think ... and "Ert", being the nantonyms of "Decrepit", Disturbed", and "Inert". Using Gaby's logic, the nantonym of "Detriment" would be "Trement".[/nq]
"Triment", surely?
Cheers, Harvey
CanEng and BrEng, indiscriminately mixed