Intermittently encounter nitwit; truly gutless lightweight (9)

I believe the answer is:

nonentity

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'gutless lightweight' is the definition.
'nonentity' can be an answer for 'lightweight' (thesaurus). I'm unsure of the 'gutless' bit.

'intermittently encounter nitwit truly' is the wordplay.
'intermittently' means one should take alternating letters.
'truly' becomes 'ty' (I can't explain this - if you can you should believe this answer much more).
'encounter'+'nitwit'='encounternitwit'
The alternating letters of 'encounternitwit' are 'nonenti'.
'nonenti'+'ty'='NONENTITY'

Can you help me to learn more?

(Other definitions for nonentity that I've seen before include "Person of no importance" , "not even second fiddle produced" , "Insignificant person" , "cipher" , "A nobody" .)

I've seen this clue in The Telegraph.

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