Curious how system creates stem (4)
I believe the answer is:
nosy
'curious' is the definition.
(similar in meaning)
I don't understand how the remainder of the clue works.
(Other definitions for nosy that I've seen before include "Prying, snoopy" , "Offensively curious or inquisitive" , "Meddlesome" , "Inquisitive in nasal manner" , "Fragrant" .)