(Britain, Ireland, colloquial) In an underhand way, sneakily; unofficially, particularly with regard to payment or tax avoidance.

Illicit, obtained or sold furtively.

A layer of short hairs underneath the longer ones of an animal's fur / A coat of paint or other material applied onto a surface before that of a topcoat; a coloured primer

(transitive) To apply an undercoat to.

(photography) To take a photograph using too small an exposure / To provide with insufficient publicity

(photography) The condition when a photograph is darker than it should be because the film was not exposed to sufficient light either because the camera aperture was too small or the duration of light was too short.

clothing worn next to the skin; underwear

To act in an understated manner or with little expressiveness

To bid too low. / To bid lower than another. / (bridge) To bid less than the full value of a hand of cards.

A bid that is lower than another.