Tie up about ten and depart (4)
I believe the answer is:
exit
'depart' is the definition.
(I know that depart is a more specific form of exit)
'tie up about ten' is the wordplay.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'about' indicates putting letters inside.
'ten' becomes 'X' (Roman numeral).
'tie' in reverse letter order is 'eit'.
'eit' going around 'x' is 'EXIT'.
'and' acts as a link.
(Other definitions for exit that I've seen before include "[DOOR] ?" , "Way to leave" , "Relinquish the lead" , "Withdrawal" , "Player's departure" .)