Man from Munster loses the head in very important county of Ireland (5)
I believe the answer is:
kerry
'county of ireland' is the definition.
(I've seen this before)
'man from munster' is the wordplay.
'man' becomes 'ker'.
'from' means one lot of letters go next to another.
'munster' becomes 'ry' (I can't explain this - if you can you should believe this answer much more).
'ker'+'ry'='KERRY'
'loses the head in very important' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for kerry that I've seen before include "County of Tralee" , "Irish county" , "County < girl" , "County of Ireland" .)