Engineers likely to be trustworthy (8)
I believe the answer is:
reliable
'be trustworthy' is the definition.
(associated in meaning)
'engineers likely' is the wordplay.
'engineers' becomes 're' (abbreviation for Royal Engineers).
'likely' becomes 'liable' (similar in meaning).
're'+'liable'='RELIABLE'
'to' acts as a link.
(Other definitions for reliable that I've seen before include "Dependable, can be trusted" , "Can be depended upon, trustworthy" , "Dependable, trustworthy" , "Dependable, honest" , "Trusty" .)