meagre, skinny / lean, thin

meagre (fish)

to abstain from meat on certain days appointed by the Roman Catholic Church

to practice abstinence (to temporarily abstain from certain types of food, especially meat and fatty foodstuffs, on certain days or at certain periods for religious reasons)

(simile) thin as a rake, thin as a wafer

plural of maigre

thinness (state of being thin) / meagreness

plural of maigreur

poorly, weakly

skinny