The force captures one crook (5)
I believe the answer is:
thief
'crook' is the definition.
(thief is a kind of crook)
'the force captures one' is the wordplay.
'force' becomes 'F' (symbol used in Physics e.g. f=ma).
'captures' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'the'+'f'='thef'
'thef' enclosing 'i' is 'THIEF'.
(Other definitions for thief that I've seen before include "'Taffy was a - - '" , "Unlawful taker" , "One's inclined to take" , "See 3" , "One with taking ways" .)