Ruining tie, getting cross in way out (4)
I believe the answer is:
exit
'way out' is the definition.
(synonyms)
'ruining tie getting cross' is the wordplay.
'ruining' indicates an anagram.
'getting' means one lot of letters goes inside another.
'cross' becomes 'x' (an X is a cross).
'tie' with letters rearranged gives 'eit'.
'eit' going around 'x' is 'EXIT'.
'in' acts as a link.
(Other definitions for exit that I've seen before include "Way to leave" , "Leave the building" , "farewell!" , "Player's departure" , "Actor's departure" .)