English
fatless
From fat + -less.
A compound of fat + -less
Proto-West Germanic *fait
Proto-West Germanic *faitijan ‘to make fat’
Proto-West Germanic *faitid ‘fatted’
Old English fǣtt ‘fatted’
Middle English fat ‘fattened’
English fat
Today it means
adj Without fat, especially in the senses: made without fat, fat-free.
Language periods are conventional ranges, not dates for this word.
Etymograph / fatless