Bow tie mostly bent back before party: one might get fixed on entrance (10)
I believe the answer is:
architrave
'one might get fixed on entrance' is the definition.
(type of architectural feature)
'bow tie mostly bent back before party' is the wordplay.
'bow' becomes 'arch' (I've seen this before).
'mostly' means to remove the last letter.
'bent back' says the letters should be written backwards.
'before party' becomes 'rave' (I've seen this before. I am not sure about the 'before' bit.**).
'tie' with its final letter removed is 'ti'.
'ti' backwards is 'it'.
'arch'+'it'+'rave'='ARCHITRAVE'
(Other definitions for architrave that I've seen before include "moulding" , "Frame for door or window" , "piece of classical temple" , "this is carried across several columns" , "Beam" .)