mole in proverbial use often referred to as the type of a blind creature. The mole was also toasted by Jacobites as the little gentleman in black velvet, in reference to the death of William III, said to have been caused by a fall from his horse which had stumbled on a molehill (the small mound of earth thrown up by a mole burrowing near the surface).

From the early 1920s, mole has been used allusively to designate a spy who achieves over a long period an important position within the security defences of a country, or someone within an organization who anonymously betrays confidential information.

See also make a mountain out of a molehill.

mole3
A. (stone) pier or breakwater, (hence) harbour
;
B. † large mass XVI. — F. môle — It. molo — medGr. môlos, mólos — L. mōlēs shapeless mass, huge bulk (whence sense B), dam, pier.

mole1 † discoloured spot OE.; spot or blemish on the human skin XIV. OE. māl, corr. to MLG. mēl, OHG. meil, meila, Goth. *mail (in g. pl. maile):- Gmc. *mailam, -ōn, whence also OE. mælan, OHG. meilen stain.