Excitement of head abandoning merrymaking (7)
I believe the answer is:
arousal
'excitement' is the definition.
(I've seen this in another clue)
'head abandoning merrymaking' is the wordplay.
'head abandoning' means to remove the first letter (I've seen 'head abandons' mean this).
'merrymaking' becomes 'carousal' (carousal is a kind of merrymaking).
'carousal' with its initial letter removed is 'AROUSAL'.
'of' is the link.
(Other definitions for arousal that I've seen before include "Awakening; stimulation" , "Act of waking (someone)" , "heating?" , "Drinking spree" , "Sexual excitement" .)