Be entirely appropriate? Only at odd intervals (8)

I believe the answer is:

fitfully

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'appropriate? only at odd intervals' is the definition.
I can't tell whether this defines the answer.

'be entirely' is the wordplay.
'be' becomes 'fit' (fitting is a kind of being).
'entirely' becomes 'fully' (I've seen this in another clue).
'fit'+'fully'='FITFULLY'

Can you help me to learn more?

(Other definitions for fitfully that I've seen before include "Only at times" , "not consistently" , "Intermittently" , "Spasmodically" , "occurring in bouts?" .)

I've seen this clue in The Times.

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