Life squashes last of your spirit (4)
I believe the answer is:
brio
'spirit' is the definition.
(I've seen this in another clue)
'life squashes last of your' is the wordplay.
'life' becomes 'bio' (life can mean a biography).
'squashes' indicates putting letters inside (some letters are squashed into a word).
'last of' says to take the final letters.
The final letter of 'your' is 'r'.
'bio' enclosing 'r' is 'BRIO'.
(Other definitions for brio that I've seen before include "Dash or verve, from Italian" , "'Liveliness, vivacity (4)'" , "Spiritedness" , "In music, con ..... means with dash and verve" , "Drive" .)