nut

noun

• 1a fruit consisting of a hard or tough shell around an edible kernel.
• the hard kernel of a nut.
• informal a person’s head.
• (usually nuts) vulgar slang testicles.

• 2a small flat piece of metal or other material, typically square or hexagonal, with a threaded hole through it for screwing onto a bolt as a fastener.
• Music the part at the lower end of the bow of a violin or similar instrument, with a screw for adjusting the tension of the hair.

• 3 informal a crazy or eccentric person.
• [with modifier] a person who is excessively interested in or enthusiastic about a specified thing:a football nut

• 4the fixed ridge on the neck of a stringed instrument over which the strings pass.

verb (nuts, nutting, nutted)

• 1 [no object] (usually as noun nutting) archaic gather nuts.

• 2 [with object] British informal butt (someone) with one’s head.