Sportsman's first sporting, using bad language (8)

I believe the answer is:

swearing

'using bad language' is the definition.
(I've seen this before)

'sportsman's first sporting' is the wordplay.
'sportsman's first' becomes 's' (1st letter of 'sportsman').
'sporting' becomes 'wearing' (I've seen this before).
's'+'wearing'='SWEARING'

(Other definitions for swearing that I've seen before include "Taking an oath" , "Expressing annoyance" , "promising" , "Vowing" , "Foul language" .)

I've seen this clue in The Telegraph.

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