mut·ton 
/ˈmʌtn̩/ noun
/ˈmʌtn̩/ noun [noncount] : the meat of an adult sheep used as food
▪ a meal of mutton and potatoes ▪ a leg/shoulder of mutton
▪ a meal of mutton and potatoes ▪ a leg/shoulder of mutton
mutton dressed as lamb
Brit, informal + disapproving : a woman who tries to make herself look younger by wearing clothes designed for young people
