Particle very much accepted by blokes (5)
I believe the answer is:
meson
'particle' is the definition.
(meson is a kind of particle)
'much accepted by blokes' is the wordplay.
'much' becomes 'so much' (similar in meaning).
'accepted by' indicates putting letters inside (inserted letters are accepted).
'blokes' becomes 'men' (bloke can informally mean a man).
'so' inserted inside 'men' is 'MESON'.
'very' acts as a link.
(Other definitions for meson that I've seen before include "Smaller particle than a proton" , "Elementary particle" , "Something small" , "tiny particle" , "Quark/antiquark particle" .)