hard as nails
Unyielding, callous, unsympathetic, as in Don't ask her for a contribution—she's hard as nails. This expression has replaced the 14th-century simile hard as flint stone and presumably alludes to the rigidity of nails.
Words nearby hard as nails
harbour seal,
harbourage,
hard,
hard act to follow,
hard and fast,
hard as nails,
hard bargain,
hard bop,
hard candy,
hard case,
hard cash
Example sentences from the Web for hard as nails
"Hard-as-nails" the girls sometimes called her, for she coddled nobody and expected the utmost from each one's capacity.
For the Sake of the School |Angela BrazilHow she come to be related to that hard-as-nails Joe Stagg is a puzzler.
Carolyn of the Corners |Ruth Belmore Endicott