Mean-spirited American blocking medicine, hatred swamping love (13)
I believe the answer is:
pusillanimous
'mean-spirited' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I don't see?
'american blocking medicine hatred swamping love' is the wordplay.
I cannot really see how this works, but
'american' could be 'us' (abbreviation for United States) and 'us' is located in the answer.
'medicine' could be 'pill' (pill is a kind of medicine) and 'pill' is found in the remaining letters.
'love' could be 'o' (love means zero in tennis) and 'o' is found within the answer.
'hatred' could be 'animus' (animus is a kind of hatred) and 'animus' is located in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for pusillanimous that I've seen before include "Craven" , "faint-hearted" , "Weak-spirited - timid" , "Timid, lacking courage" , "Lacking determination" .)