Incline to be skinny (4)
I believe the answer is:
lean
I believe this is a triple definition!
'incline' is the first definition.
(I know that incline is a kind of lean)
'to be' is the second definition.
(leaning is a kind of being)
'skinny' is the third definition.
(similar in meaning)
(Other definitions for lean that I've seen before include "Slope; thin" , "Incline to prop against" , "David ..., director of Ryan's Daughter" , "Incline; without fat" , "Thin; heel" .)