Scared, having a security device (7)
I believe the answer is:
alarmed
'scared' is the definition.
(alarming is a kind of scaring)
'a security device' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
'device' could be 'arm' (arm is a kind of device) and 'arm' is found within the answer.
The remaining letters 'led' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'having' acts as a link.
Can you help me to learn more?
(Other definitions for alarmed that I've seen before include "Filled with apprehension" , "Apprehensive" , "In a panic" , "Frightened, disturbed" , "Terrified" .)