A new job's endless security (6)
I believe the answer is:
anchor
'security' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for anchor that I've seen before include "Ship's mooring device" , "ground" , "Ship's holding device" , "secured by a fluke" , "Something (or someone) providing stability" .)