Definition of "undermanager"

Despite the effects of the disease, he was subsequently promoted to overman and thereafter to undermanager.

1980, Great Britain. Dept. of Health and Social Security, Reported Decisions of the Social Security Commissioner

The undermanager, on duty at reception, could have made a living in World War II movies.

2012, John Gardner, Death is Forever

I mean, all the lasses will be after him, him being an undermanager. An' then, he's getting old now, he must be nearly thirty. Nobody gets to be an undermanager lest they're getting on a bit, never mind how clever they are.

2017, Maggie Hope, The Coal Miner's Daughter