Strange of Irish to keep potential worker in isolation (10)
I believe the answer is:
quarantine
'isolation' is the definition.
(I know that quarantine is a type of isolation)
'strange of irish to keep potential worker in' is the wordplay.
'strange of irish' becomes 'quare' (Irish form of 'queer').
'to keep' is an insertion indicator.
'potential worker' becomes 'ant' (worker is a type of ant).
'ant'+'in'='antin'
'quare' going around 'antin' is 'QUARANTINE'.
(Other definitions for quarantine that I've seen before include "separate from others" , "Period of isolation to prevent spread of disease" , "Precautionary seclusion" , "Period of enforced isolation" , "solitary confinement" .)