under the table

Short definition from Wiktionary

Prepositional phrase

1. 1
   Secret; covert; undisclosed.
2. 2
   Secretly; covertly; undisclosedly.
3. 3
   In or into a state of stupification or boredom.
4. 4
   In or into a state of drunkenness.
5. 5
   Used other than figuratively or idiomatically: see under, table.

Adjective

1. 1
   Alternative spelling of under the table; in attributive use.