Strapping left in place (5)
I believe the answer is:
burly
'strapping' is the definition.
(synonyms)
'left in place' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' means one lot of letters goes inside another.
'place' becomes 'bury' (I am not sure about this - if you are sure you should believe this answer much more).
'l' put inside 'bury' is 'BURLY'.
Can you help me to learn more?
(Other definitions for burly that I've seen before include "Big and thickset" , "Big and sturdy" , "Beefy" , "Sturdily built" , "Strongly and heavily built" .)