Strong worker extremely friendly (5)
I believe the answer is:
beefy
'strong' is the definition.
(synonyms)
'worker extremely friendly' is the wordplay.
'worker' becomes 'bee' (a worker bee).
'extremely' suggests removing the centre (only the extremes of the word are used).
'friendly' with its centre taken out is 'fy'.
'bee'+'fy'='BEEFY'
(Other definitions for beefy that I've seen before include "Burly" , "Athletic and muscular (non-vegetarian?)" , "Colloquially muscular" , "Muscularly well-developed" , "Muscular, robust" .)