Seer is out to get the Irish (4)
I believe the answer is:
erse
'the irish' is the definition.
(I've seen this before)
'seer is out' is the wordplay.
'is out' indicates anagramming the letters (I've seen 'was out' mean this).
'seer' anagrammed gives 'ERSE'.
'to get' is the link.
(Other definitions for erse that I've seen before include "Old language spoken by strange seer" , "Name sometimes given to languages of the Celts in Ireland and Scotland" , "Irish Gaelic language" , "Old Scots or Irish Gaelic" , "Old Celtic language" .)