Fit old man's back caught in elastic (10)

I believe the answer is:

applicable

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'fit' is the definition.
(thesaurus)

'old man's back caught in elastic' is the wordplay.
'old man's back' becomes 'ap' (I can't explain this - if you can you should believe this answer much more).
'caught' becomes 'c' (cricket abbreviation).
'in' indicates putting letters inside.
'elastic' becomes 'pliable' ('pliable' can be a synonym of 'elastic').
'c' placed into 'pliable' is 'plicable'.
'ap'+'plicable'='APPLICABLE'

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(Other definitions for applicable that I've seen before include "Relevant, appropriate" , "Suitable" .)

I've seen this clue in The Telegraph.

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