Kiss him excitedly around end of December and fight! (8)
I believe the answer is:
skirmish
'fight' is the definition.
(skirmishing is a kind of fighting)
'kiss him excitedly around end of december' is the wordplay.
'excitedly' indicates anagramming the letters.
'around' is an insertion indicator.
'end of' says to take the final letters.
The last letter of 'december' is 'r'.
'kiss'+'him'='kisshim'
'kisshim' with letters rearranged gives 'skimish'.
'skimish' enclosing 'r' is 'SKIRMISH'.
'and' acts as a link.
(Other definitions for skirmish that I've seen before include "clash" , "offensive" , "Minor military engagement" , "Brief military engagement" , "Small battle" .)