Free muscles needing source of oil without iodine (7)
I believe the answer is:
absolve
'free' is the definition.
(to absolve is to free or spare from blame)
'muscles needing source of oil without iodine' is the wordplay.
'muscles' becomes 'abs' (short for abdominals).
'needing' says to put letters next to each other.
'source of oil' becomes 'olive' (as in olive oil).
'without' is a deletion indicator.
'iodine' becomes 'I' (chemical symbol).
'olive' with 'i' taken away is 'olve'.
'abs'+'olve'='ABSOLVE'
(Other definitions for absolve that I've seen before include "Declare to be free from blame" , "Give pardon" , "Grant pardon for" , "Declare (someone) guilt-free" , "Grant remission of a sin" .)