He comes across as a false friend (6)
I believe the answer is:
finder
'he comes across' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'a false friend' is the wordplay.
'a false' is an anagram indicator.
'friend' with letters rearranged gives 'FINDER'.
'as' is the link.
Can you help me to learn more?
(Other definitions for finder that I've seen before include "One making discovery" , "May one keep" , "keeper, they say" , "instrument used to locate a target" , "Locator (of an object)" .)