Understanding popular view (7)
I believe the answer is:
insight
'understanding' is the definition.
(I know that insight is a type of understanding)
'popular view' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'view' becomes 'sight' (synonyms).
'in'+'sight'='INSIGHT'
(Other definitions for insight that I've seen before include "ability to perceive clearly" , "Visible" , "Perceptiveness" , "Special knowledge" , "comprehension" .)