Importance publication attached to naked figure full of sex appeal (9)
I believe the answer is:
magnitude
'importance' is the definition.
(magnitude is a kind of importance)
'publication attached to naked figure full of sex appeal' is the wordplay.
'publication' becomes 'mag' (abbreviation for magazine).
'attached to' is a charade indicator (letters next to each other).
'naked figure' becomes 'nude' (I've seen this before).
'full of' indicates putting letters inside.
'sex appeal' becomes 'it'.
'nude' enclosing 'it' is 'nitude'.
'mag'+'nitude'='MAGNITUDE'
(Other definitions for magnitude that I've seen before include "Dimensions" , "Relative importance" , "Eating mud (anag.)" , "(A star's) brightness" , "Largeness or size" .)