Common words found in signal successfully reversed (5)
I believe the answer is:
slang
'common words' is the definition.
(common or colloquial language)
'in signal successfully reversed' is the wordplay.
'in' indicates a hidden word.
'reversed' says the letters should be written in reverse.
'gnals' is hidden in the letters of 'signal successfully'.
'gnals' written backwards gives 'SLANG'.
'found' is the link.
(Other definitions for slang that I've seen before include "Be abusive" , "Informal language - jargon" , "colloquialisms" , "Non-standard vocabulary" , "form of language" .)