Inconsiderate aunt exposed family in article (10)
I believe the answer is:
unthinking
'inconsiderate' is the definition.
(similar in meaning)
'aunt exposed family in article' is the wordplay.
'exposed' means to look at the middle letters (the inside of the word is exposed).
'family' becomes 'kin' (synonyms).
'in' means one lot of letters goes inside another.
'article' becomes 'thing' (both can mean an object).
The middle of 'aunt' is 'un'.
'kin' going into 'thing' is 'thinking'.
'un'+'thinking'='UNTHINKING'
(Other definitions for unthinking that I've seen before include "inconsiderate" , "Knee-jerk" .)