Draw security device (8)
I believe the answer is:
deadlock
'draw security device' is the definition.
'deadlock' can be an answer for 'draw' (thesaurus). I am unsure of the 'security device' bit.
'draw security device' is the wordplay.
'draw' becomes 'dead' (I can't justify this - if you can you should believe this answer much more).
'security device' becomes 'lock' (I've seen this in another clue).
'dead'+'lock'='DEADLOCK'
Can you help me to learn more?
(Other definitions for deadlock that I've seen before include "Something opened by a key - stalemate" , "Impasse, standoff" , "Situation from which no progress can be made" , "Log jam" , "tie" .)