a small metal spike with a flat head, used to join things together

firm and decisive in speech or action; categorical and unhesitating

Oncomelania (a genus of small freshwater snails)

a thorn in one's side

a householder who refuses to vacate his home despite pressure from property developers

settled or unalterable; something that is certain or cannot be changed

thumbtack; drawing pin

to meet with a rebuff

A tactful, polite, or subtle retort or rejection that is difficult to respond to directly.

nail hammer or claw hammer

to secure a nail by bending back the protruding end

to follow someone secretly to monitor their movements

cramp (a metal fastener used in construction)

nail gun; staple gun

to put to death by nailing to a cross or by impalement

DingTalk, a business communication and collaboration platform developed by Alibaba

stud (for decorating clothing, shoes, belts etc)

nose stud; nose piercing

staple (stationery)

hexagon socket head cap screw

a short nail or pin with a large, flat head used for fastening paper to a surface

nail gun or stud gun

to make doubly sure (idiom)

a "screw that never rusts" – metaphor used in CCP propaganda to praise loyal, selfless contributors, famously applied to model worker Lei Feng

a thorn in one's side

a metaphor for a flat refusal, a harsh rejection, or a difficult obstacle that is hard to deal with

button magnet (to use on whiteboards, refrigerator doors etc)

a small earring shaped like a stud

a piece of jewelry, typically a barbell or ring, inserted through a piercing in the tongue

a small, slender nail with a minimal head, used in finish carpentry and picture framing to avoid splitting the wood

The Nine-Toothed Rake, the signature weapon used by Zhu Bajie in the novel Journey to the West.

head of a nail

being conscientious and precise in one's work or behavior; showing great attention to detail