Avoid each concealed notion (4)
I believe the answer is:
idea
'notion' is the definition.
(thesaurus)
'avoid each concealed' is the wordplay.
'concealed' says the answer is hidden in the clue.
'IDEA' is hidden in the letters of 'avoid each'.
(Other definitions for idea that I've seen before include "A suspicion of" , "a wheeze" , "Notion, image" , "Notion, concept" , "Aim" .)