Knowledge from Albigensians (3)
I believe the answer is:
gen
'knowledge' is the definition.
(I've seen this before)
'from albigensians' is the wordplay.
'from' indicates a hidden word.
'GEN' can be found hidden inside 'albigensians'.
(Other definitions for gen that I've seen before include "'Information, colloquially (3)'" , "opening book, in short" , "Information yielded" , "Knowledge" , "Information (colloq.)" .)