Irishman finds hard way (4)
I believe the answer is:
path
'way' is the definition.
(I know that way can be written as path)
'irishman finds hard' is the wordplay.
'irishman' becomes 'Pat' (Patrick is a common Irish name).
'finds' means one lot of letters go next to another.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'pat'+'h'='PATH'
(Other definitions for path that I've seen before include "Walkway" , "Pavement" , "Track, way for walkers" , "trail" , "Pedestrian way" .)