Events prevent models working without underwear, ultimately (12)
I believe the answer is:
developments
'events' is the definition.
(development is a kind of event)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for developments that I've seen before include "Evolutions" , "Advances in a process" , "MTD envelopes (anag.)" , "Move Len's dept (anag.)" , "Progressive changes" .)