Impertinence involving naughty nude in a row (5,2)
I believe the answer is:
lined up
'in a row' is the definition.
(as in being lined up in a row)
'impertinence involving naughty nude' is the wordplay.
'impertinence' becomes 'lip' (lip is a kind of impertinence).
'involving' means one lot of letters goes inside another.
'naughty' indicates an anagram.
'nude' anagrammed gives 'nedu'.
'lip' enclosing 'nedu' is 'LINED UP'.
(Other definitions for lined up that I've seen before include "Arranged" , "In a row" .)