Get rid of the first letter in Irish (5)
I believe the answer is:
erase
'get rid of' is the definition.
(I've seen this in another clue)
'first letter in irish' is the wordplay.
'first letter' becomes 'a' (in the alphabet).
'in' means one lot of letters goes inside another.
'irish' becomes 'erse' (I've seen this before).
'a' put inside 'erse' is 'ERASE'.
'the' acts as a link.
(Other definitions for erase that I've seen before include "Destroy recording on audio or video tape" , "Remove, wipe out" , "Clear" , "Remove recorded material" , "Remove evidence of" .)