under the counter

/ˌʌndər ðə ˈkaʊntər/
adjective
  1. Done or sold secretly and illegally, especially in a way that avoids taxes or regulations.
    • The restaurant paid its workers under-the-counter wages to avoid payroll taxes.
    • He bought under-the-counter cigarettes from a shop that didn't display them.
    • During the shortage, some stores sold goods under-the-counter at inflated prices.
What does "under the counter" mean? | whatsthatwordmean | whatsthatwordmean