Definition of MOLE

: any of numerous burrowing insectivores (especially family Talpidae) with tiny eyes, concealed ears, and soft fur

: one who works in the dark

: a machine for tunneling

: a spy (such as a double agent) who establishes a cover long before beginning espionage

broadly : one within an organization who passes on information

: a massive work formed of masonry and large stones or earth laid in the sea as a pier or breakwater

: the harbor formed by a mole

Noun (2)

for years we have had a mole in the enemy's national intelligence agency

Recent Examples on the Web

Daniel Solis, the FBI mole whose undercover work led to charges against both Burke and then-House Speaker Michael Madigan, whose own racketeering trial is now in the hands of a jury. —Jason Meisner, Chicago Tribune, 30 Jan. 2025 Following season 2's dramatic ending, which unveiled part of a plot to steal the presidency, Basso agrees to be Catherine's mole. —Emily Blackwood, People.com, 25 Jan. 2025 Tracing the mole’s evolutionary heritage For years the marsupial mole’s strange, specialised traits have frustrated attempts to determine precisely who its closest relatives actually are. —Charles Feigin / The Conversation, Popular Science, 23 Jan. 2025 Noticing any new changes to your skin, especially if a new growth pops up, only naturally sets off a series of internal alarm bells: Is that a mole, a wart, a melanoma? —Caroline C. Boyle, USA TODAY, 22 Jan. 2025 See all Example Sentences for mole 

Etymology

Noun (1)

Middle English, from Old English māl; akin to Old High German meil spot

Noun (2)

Middle English; akin to Middle Low German mol

Noun (3)

Middle English, from Latin mola mole, literally, mill, millstone — more at mill

Noun (4)

Middle French, from Old Italian molo, from Late Greek mōlos, from Latin moles, literally, mass, exertion; akin to Greek mōlos exertion

Noun (5)

German Mol, short for Molekulargewicht molecular weight, from molekular molecular + Gewicht weight

Noun (6)

Mexican Spanish, from Nahuatl mōlli sauce

First Known Use

Noun (1)

14th century, in the meaning defined above

Noun (2)

14th century, in the meaning defined at sense 1

Noun (3)

15th century, in the meaning defined above

Noun (4)

circa 1548, in the meaning defined at sense 1

Noun (5)

1902, in the meaning defined above

Noun (6)

1882, in the meaning defined above

Time Traveler

The first known use of mole was in the 14th century