IPA: /ˈfɪtə/
KK: /ˈfɪtər/
More suitable or appropriate for a particular purpose or situation than something else.
She is fitter than she was last year after starting her new exercise routine.
Comparative: fitter
Superlative: fittest
A person whose job is to fit or assemble parts or equipment together.
The fitter carefully installed the new windows in the building.
Fitter → It is formed from "fit" (from Old English *fittan*, meaning to make fit or suitable) and "-er" (meaning a person who). The word "fitter" refers to a person who makes something fit or suitable.
Think of someone who makes things 'suitable' or 'fit' — that's what a fitter does.