There's nothing in lining up (3)
I believe the answer is:
nil
'there's nothing' is the definition.
(nil means a score of zero in football)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for nil that I've seen before include "Nothing found in senility" , "Nothing - in Latin" , "There's nothing left" , "Lacking value" , "Zero, no score" .)