Lieutenant initially laid into lusty corporal (7)
I believe the answer is:
earthly
'corporal' is the definition.
(both can mean of the body as opposed to the spirit)
'lieutenant initially laid into lusty' is the wordplay.
'initially' suggests taking the first letters.
'laid into' indicates putting letters inside.
'lusty' becomes 'earthy' (both can mean sexually vulgar).
The initial letter of 'lieutenant' is 'l'.
'l' going inside 'earthy' is 'EARTHLY'.
(Other definitions for earthly that I've seen before include "Of this world" , "No such possible chance" , "Relating to material things" , "Relating to material existence as distinct from a spiritual one" , "Material; worldly" .)