Row and fight starting off is witnessed on rugby pitch
I believe the answer is:
line-out
'witnessed on rugby pitch' is the definition.
The definition suggests a singular noun which matches the answer.
'row and fight starting off' is the wordplay.
'row' becomes 'line' (I've seen this before).
'and' is a charade indicator (letters next to each other).
'fight' becomes 'bout' ('bout' can be a synonym of 'fight').
'starting off' means to remove the first letter (the starting letter is removed).
'bout' with its initial letter removed is 'out'.
'line'+'out'='LINE-OUT'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for line-out that I've seen before include "Method of restarting play in rugby" , "Outline for a rugby formation" , "Set piece of play in rugby" , "Rugby re-start" , "A standing rugby formation" .)