Where does this definition of as hard as nails come from?
This entry for as hard as nails is sourced from Main Dictionary, one of the dictionaries and corpora merged into Lughet.
Is as hard as nails a noun, verb, or something else?
In this entry, as hard as nails is tagged as 2adv..
What is Lughet?
Lughet is a free trilingual dictionary covering nearly five million entries across Uyghur, Chinese, and English, drawn from more than ten source dictionaries and corpora.