fitter

Etymology 1

fit (verb) + -er

noun

1. A person who fits or assembles something.
   a fitter of clothing, or of machinery
   But in the early days of the scheme the new machines created some problems for the fitters, who found them over-complex and their faults hard to diagnose after many years' experience of small, simple steam locomotives. 1962 October, M. J. Wilson, “Three years of dieselisation at Devons Road depot”, in Modern Railways, pages 262, 264
   "They have gone past their sell-by date. But the fitters have done an amazing job keeping these units running for as long as they have. January 13 2021, Paul Clifton, “Network News: Island Line bids farewell to 1930s "icon of transport"...”, in Rail, page 8
2. (informal) An epileptic.
3. (UK, dated) A coal broker who conducts the sales between the owner of a coal pit and the shipper.
4. (film, historical) A person employed to find suitable music to accompany silent films.
   For the fitter of film music in the silent era visual reference was the surest indicator of content. 2012, Stephen Neale, The Classical Hollywood Reader, page 268

Etymology 2

fit (adjective) + -er

adj

1. comparative form of fit: more fit
   An exercise bike won't make you fitter if you never find time to use it.
   My bird's loads fitter than yours.
   All stood together on the deck, / For a charnel-dungeon fitter: / All fixed on me their stony eyes, / That in the Moon did glitter. 1798, Samuel Taylor Coleridge, The Rime of the Ancient Mariner