Curious dog (6)
I believe the answer is:
snoopy
I believe this clue is a double definition.
'curious' is the first definition.
(similar in meaning)
'dog' is the second definition.
(I've seen this before)
(Other definitions for snoopy that I've seen before include "Prying, as in Peanuts" , "Charlie Brown's canine companion" , "Curious" , "Brown dog's" , "Cartoon beagle" .)