Leader of America and West remains inundated (5)
I believe the answer is:
awash
'inundated' is the definition.
(thesaurus)
'leader of america and west remains' is the wordplay.
'leader of' indicates taking the first letters.
'and' means one lot of letters go next to another.
'west' becomes 'w' ('W' can be a synonym of 'west').
'remains' becomes 'ash' (I've seen this before).
The first letter of 'america' is 'a'.
'a'+'w'+'ash'='AWASH'
(Other definitions for awash that I've seen before include "Doused in water" , "Overflowing" , "Drenched" , "Deluged" , "Swimming" .)