Partly discovering poetic Ireland (4)
I believe the answer is:
erin
'poetic ireland' is the definition.
(I've seen this before)
'partly discovering' is the wordplay.
'partly' says the answer is hidden in the clue.
'ERIN' is hidden within 'discovering'.
(Other definitions for erin that I've seen before include "Poetically, Ireland" , "Early and poetic name here" , "Ireland (poet.)" , "Romantic, archaic name for Ireland" , "(Literary name for) Ireland" .)