Be untruthful about for example being loyal (5)
I believe the answer is:
liege
'loyal' is the definition.
(similar in meaning)
'be untruthful about for example' is the wordplay.
'be untruthful' becomes 'lie' (I've seen this in another clue).
'about' says the letters should be written in reverse.
'for example' becomes 'e.g.' (short for 'exempli gratia', 'for example' in Latin).
'eg' reversed gives 'ge'.
'lie'+'ge'='LIEGE'
'being' is the link.
(Other definitions for liege that I've seen before include "Belgian city or feudal chief" , "City in eastern Belgium" , "Chieftain" , "European province" , "A person holding land under feudalism" .)