be mutton dressed as lamb

be mutton dressed as lamb

To be an older woman who is trying unsuccessfully to look much younger or else finds herself attractive in the style of younger women. This term is usually disparaging. Primarily heard in UK. I don't know what she's thinking wearing a dress like that. She looks like mutton dressed as lamb!
See also: dress, lamb, mutton

be mutton dressed (up) as ˈlamb

(British English, informal, disapproving) used to describe a woman who is trying to look younger than she really is, especially by wearing clothes that are designed for young people: Have you seen her? Mutton dressed as lamb. Somebody should remind her that she’s 55, not 25.
Mutton is the meat from an adult sheep, while lamb is the meat from a young sheep.
See also: dress, lamb, mutton