Gruelling contest takes a month, attracting most of Irish town (9)
I believe the answer is:
decathlon
'gruelling contest' is the definition.
'decathlon' can be an answer for 'contest' (decathlon is a kind of contest). I'm unsure of the 'gruelling' bit.
'a month attracting most of irish town' is the wordplay.
'a month' becomes 'Dec' (abbreviation for December).
'attracting' means one lot of letters go next to another.
'most of' means to remove the last letter.
'irish town' becomes 'athlone' (town in Ireland).
'athlone' with its last letter taken off is 'athlon'.
'dec'+'athlon'='DECATHLON'
'takes' acts as a link.
Can you help me to learn more?
(Other definitions for decathlon that I've seen before include "Athletic event" , "Series of events" , "Athletic contest with ten different events" , "Olympic athletics event" , "Latched on to athletic competition of 10 events" .)