(v.) Shooting a gun loaded with 'blank' rounds that create smoke and noise, but bear no fruit from the barrel.
(v.) Ejaculating/shooting a penis which is impotent (the seminal fluid cannot contain sperm, hence it is 'blank'). After the owner of the penis going through the motions and making noise no fruit is born of the barrel.
When some resigns or retires from a job, they are on "eternity leave". This can also refer to someone who has passed away, especially someone who worked somewhere for a long time, retired/resigned, then passed away later.
Oh I'm sorry, you didn't know that Kelly is on eternity leave? She resigned and moved to Hawaii!
With regrets I would like to inform you that my boss is officially on eternity leave. I will never see or hear them again. Ever.