Getting cross on mother's day of celebration (4)
I believe the answer is:
xmas
'celebration' is the definition.
(I have seen 'Short celebration' mean 'xmas' so perhaps 'celebration' could also mean 'xmas')
'getting cross on mother's day' is the wordplay.
I cannot quite see how this works, but
'cross' could be 'x' (X is cross-shaped) and 'x' is found within the answer.
'mother's' could be 'mas' (ma can mean mother) and 'mas' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for xmas that I've seen before include "present time" , "Short celebration" , "Abbreviation for a winter festival" , "Christmas (abbrev.)" , "Short for Christmas" .)