1824, colloquial abbreviation of Latin infra dignitatem "beneath the dignity of."
The rest of us feel that it's infra dig., and hope nobody will find out that we ever worked with our hands for a living.
"infra dig.," he went on, with a humorous side-glance, and without pausing for my answer.
She hated having to say this sort of thing to a butler, it was so infra dig.; but what could you do with father?