DIPSTICK

dipstick

(noun) a graduated rod dipped into a container to indicate the fluid level

Source: WordNet® 3.1

Etymology

Noun

dipstick (plural dipsticks)

A stick or rod used to measure the depth of a liquid. Often used to check the level at which a liquid in an opaque or inaccessible tank or reservoir stands; gauge.

(slang) A penis.

(slang) A useless person of inferior intellect; a dipshit.

Verb

dipstick (third-person singular simple present dipsticks, present participle dipsticking, simple past and past participle dipsticked)

To check (a person) for their understanding of something, as of a lesson, or attitude toward something.

Source: Wiktionary