Engineers can lie about dependence (8)
I believe the answer is:
reliance
'dependence' is the definition.
(I know that reliance is a type of dependence)
'engineers can lie about' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'about' indicates an anagram.
'can'+'lie'='canlie'
'canlie' with letters rearranged gives 'liance'.
're'+'liance'='RELIANCE'
(Other definitions for reliance that I've seen before include "Dependence, trust" , "Trust or confidence" , "Dependence (on something)" , "Banking" , "Trust - in cereal (anag)" .)