With second learner I leave Irish town (5)
I believe the answer is:
sligo
'irish town' is the definition.
(I've seen this before)
'with second learner i leave' is the wordplay.
'with' says to put letters next to each other.
'second' becomes 's' (common abbreviation).
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'leave' becomes 'go' (to go is to depart or leave).
's' put next to 'l' is 'sl'.
'sl'+'i'+'go'='SLIGO'
(Other definitions for sligo that I've seen before include "Town in north-west Ireland" , "one of twenty-six" , "Ir. town by Donegal bay" , "County of NW Eire" , "Yeat's county" .)