Energy zero — not moving! (5)

I believe the answer is:

oomph

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'energy' is the definition.
(oomph can mean energy or excitement)

'zero not moving' is the wordplay.
'zero' becomes 'O' (O resembles 0).
'not' becomes 'o' (I've seen this in other clues).
'moving' becomes 'mph' (I can't justify this - if you can you should believe this answer much more).
'o'+'o'+'mph'='OOMPH'

Can you help me to learn more?

(Other definitions for oomph that I've seen before include "Dynamism" , "drive" , "vital quality" , "15 [SEXINESS]" , "Sexy, exciting quality" .)

I've seen this clue in The Guardian.

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