Intruder (10)
'intruder' is the definition.
(I know that intruder can be written as interloper)
This is all the clue.
(Other definitions for interloper that I've seen before include "one entering uninvited" , "one who gatecrashes" , "Uninvited attendee" , "Intruder" .)
'intruder' is the definition.
(I know that invader is a type of intruder)
This is the entire clue.
(Other definitions for invader that I've seen before include "Encroacher" , "Trespasser" , "Military intruder" , "One enters by force to conquer" , "One illegally entering" .)