Beginning to tire, school in terribly important, passionate game? (6,6)

I believe the answer is:

tonsil hockey

'passionate game?' is the definition.

'beginning to tire school in terribly important' is the wordplay.
'beginning to' indicates taking the first letters.
'terribly' indicates an anagram.
'important' becomes 'key' ('key' can be similar in meaning to 'important').
The initial letter of 'tire' is 't'.
'school'+'in'='schoolin'
'schoolin' is an anagram of 'onsilhoc'.
't'+'onsilhoc'+'key'='TONSIL HOCKEY'

I've seen this clue in The Guardian.

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