Denial from fellow American in concrete (7)
I believe the answer is:
refusal
'denial' is the definition.
(refusal is a kind of denial)
'fellow american in concrete' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'american' becomes 'us'.
'in' indicates putting letters inside.
'concrete' becomes 'real' ('real' can be similar in meaning to 'concrete').
'f'+'us'='fus'
'fus' going into 'real' is 'REFUSAL'.
'from' acts as a link.
(Other definitions for refusal that I've seen before include "Act of declining to take or accept something" , "Horse's action in declining to jump a fence" , "The turning down of a request" , "Failure to accept" , "Rejection; turning-down" .)