From Longman Dictionary of Contemporary Englishldoce_238_fnutnut1 /nʌt/ ●●● S3 noun [countable] 1 foodDFHBP a dry brown fruit inside a hard shell, that grows on a tree a pine nut roasted nuts We were sitting round the fire cracking nuts (=opening them).2 
toolTD a small piece of metal with a hole through the middle which is screwed onto a bolt to fasten things together Use a wrench to loosen the nut.3 crazy person informalCRAZY someone who is crazy or behaves strangely My dad is such a nut. What are you, some kind of nut?4 → golf/opera etc nut5 → nuts6 → the nuts and bolts of something7 → tough/hard nut8 → a hard/tough nut to crack9 → be off your nut10 → do your nut11 head British English spoken old-fashionedINTELLIGENT your head or brainsomebody’s nut Oh come on, use your nut!
toolTD a small piece of metal with a hole through the middle which is screwed onto a bolt to fasten things together Use a wrench to loosen the nut.3 crazy person informalCRAZY someone who is crazy or behaves strangely My dad is such a nut. What are you, some kind of nut?4 → golf/opera etc nut5 → nuts6 → the nuts and bolts of something7 → tough/hard nut8 → a hard/tough nut to crack9 → be off your nut10 → do your nut11 head British English spoken old-fashionedINTELLIGENT your head or brainsomebody’s nut Oh come on, use your nut!Examples from the Corpus
nut• Eleanor is such a nut.• Add nut mixture and spread evenly.• a cashew nut• A lot of people think he's a complete nut, but he's actually quite harmless.• It lasts from nuts to soup.• In other words it has more to do with an ambitious political undertaking than with institutional nuts and bolts.• His winning concoction was Macadamia Fudge Torte: chocolate cake with fudge-filled cavities, topped by macadamia nut streusel.• Hurry up, I'm freezing my nuts off out here.• He started asking me a lot of questions about my personal life. I think the guy's some kind of nut.• a selection of nuts• The woman sounds like a real nut.• Also, the D-32's nut has a nasty sharp corner on the treble side.• Fakhru rubbed one smooth slice with his thumb and then placed the spotted nut slice on his protruding tongue.• They would sip sherry or port, nibble at the nuts and raisins and allow themselves to wallow in the warm softness.• They put him in with the nut cases.cracking nuts• Teeth are especially worthy of admiration, being capable, with proper maintenance, of cracking nuts for something like forty years.use ... nut• It can also be used on stiff nuts.• They should not be used for turning nuts which are to be used again.nutnut2 verb (nutted, nutting) [transitive] British English spoken HITto hit someone with your head SYN headbutt He just turned round and nutted me!→ See Verb tableExamples from the Corpus
nut• Bradshaw rather unwisely greeted McLean's arrival in the ring by nutting him.NUT, thethe NUTNUT, the /ˌen juː ˈtiː/ (the National Union of Teachers) one of the main professional trade unions which represents teachers in England and Wales, in both government and private schoolsOrigin nut Old English hnutu 