A foreign saint (5)
I believe the answer is:
santa
'a foreign saint' is the definition.
The definition suggests a singular noun which matches the answer.
'a foreign saint' is the wordplay.
I cannot really understand how this works, but
'a' could be 'an' and 'an' is located in the answer.
'saint' could be 'st' (abbreviation) and 'st' is present in the leftover letters.
A single letter 'a' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for santa that I've seen before include "The present chap" , "Man with sack" , "St Nicholas" , "bringer of gifts" , "patron at Christmas" .)