Directional sign, oddly awry, leading to argument (5)
I believe the answer is:
arrow
'directional sign' is the definition.
(I've seen this in another clue)
'oddly awry leading to argument' is the wordplay.
'oddly' indicates alternate letters (letters in odd-numbered positions).
'leading to' means one lot of letters go next to another (some letters go before or lead others).
'argument' becomes 'row' (to row is to argue).
The alternate letters of 'awry' are 'ar'.
'ar'+'row'='ARROW'
(Other definitions for arrow that I've seen before include "The bowman's missile" , "Missile of the archer" , "Move quickly" , "Keepsake" , "Sharp-tipped missile" .)