Translation guide
The English word "nail" has two main meanings: the hard part at the end of fingers and toes, and a small metal spike used in construction. These are completely different words in Japanese.
The hard part at the end of a finger or toe.
General word for nail (fingernail or toenail).
爪を切る。
I cut my nails.
Literally "finger nail", used when you need to specify fingernail as opposed to toenail.
指の爪を噛む癖がある。
I have a habit of biting my fingernails.
Literally "foot nail", used to specify toenail.
足の爪が厚くなった。
My toenails have become thick.
A small metal spike with a flat head, hammered into wood or other materials to join them.
Standard word for a metal nail used in carpentry or construction.
These are completely different words. 爪 (つめ) is for body parts, 釘 (くぎ) is for hardware. Using the wrong one will cause confusion.
My nails have grown.
釘を打つ。
I hammer a nail.
この板は釘で留めてある。
This board is fastened with nails.
Loanword from English, used mainly in the context of nail art or beauty, not for construction nails.
ネイルサロンに行く。
I go to a nail salon.