It's lawful for example in all construction (5)
I believe the answer is:
legal
'it's lawful' is the definition.
(similar in meaning)
'example in all construction' is the wordplay.
'example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'in' is an insertion indicator.
'construction' indicates an anagram (answer constructed from certain letters).
'all' with letters rearranged gives 'lal'.
'eg' put into 'lal' is 'LEGAL'.
'for' acts as a link.
(Other definitions for legal that I've seen before include "Compliant with the law" , "Rightful" , "sanctioned" , "Lawful" , "OK as an immigrant?" .)