Flipping Christmas at home, initially eating like a lion (7)
I believe the answer is:
leonine
'like a lion' is the definition.
(I've seen this before)
'flipping christmas at home initially eating' is the wordplay.
'flipping' is a reversal indicator.
'christmas' becomes 'noel' ('Noel' can be a synonym of 'christmas').
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'initially' suggests taking the first letters.
The first letter of 'eating' is 'e'.
'noel' back-to-front is 'leon'.
'leon'+'in'+'e'='LEONINE'
(Other definitions for leonine that I've seen before include "Resembling lions" , "Like the king of the jungle" , "None lie (anag) - like a lion" , "Beastly" , "Resembling a big cat" .)