Fear American muscle is in the way (7)
I believe the answer is:
suspect
'fear' is the definition.
(thesaurus)
'american muscle is in the way' is the wordplay.
'american' becomes 'US' (United States).
'muscle' becomes 'pec' (pectoral muscle).
'is in the' indicates putting letters inside.
'way' becomes 'st' (abbreviation for street).
'us'+'pec'='uspec'
'uspec' inserted inside 'st' is 'SUSPECT'.
(Other definitions for suspect that I've seen before include "One thought to have committed crime" , "Funny" , "Believe without being certain" , "Doubt innocence of" , "Person being accused" .)