Second casual remark about regular type of rugby game (5-1-4)
I believe the answer is:
seven-a-side
'type of rugby game' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'second casual remark about regular' is the wordplay.
I cannot quite understand how this works, but
'second' could be 's' (common abbreviation) and 's' is present in the answer.
'remark' could be 'aside' (I have seen 'Confidential remark' mean 'aside' so perhaps 'remark' could also mean 'aside') and 'aside' is present in the answer.
'regular' could be 'even' (synonyms) and 'even' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?