nut 
/ˈnʌt/ noun
plural nuts /ˈnʌt/ noun 1 [count] a : a small dry fruit with a hard shell that grows on trees, bushes, etc.
▪ The squirrel cracked/opened the nut and ate the meat inside. ▪ walnuts, almonds, peanuts, and other nuts — see picture on next page
b : the inside part of a nut that is used as food
▪ The squirrel sat and ate the nut. ▪ Are you allergic to nuts? ▪ a bowl of nuts and raisins 2 [count] : a piece of metal that has a hole through it so that it can be screwed onto a bolt or screw — see picture at carpentry; see also lug nut, wing nut 3 [count] informal a : a crazy or strange person
▪ That guy is a real nut.
b : a person who is very interested in or enthusiastic about something
▪ She's a real baseball/car/health/movie/travel nut. 4 nuts [plural] informal + impolite : a man's testicles
▪ He got kicked in the nuts.
▪ The squirrel cracked/opened the nut and ate the meat inside. ▪ walnuts, almonds, peanuts, and other nuts — see picture on next page
b : the inside part of a nut that is used as food
▪ The squirrel sat and ate the nut. ▪ Are you allergic to nuts? ▪ a bowl of nuts and raisins
▪ That guy is a real nut.
b : a person who is very interested in or enthusiastic about something
▪ She's a real baseball/car/health/movie/travel nut.
▪ He got kicked in the nuts.
a hard/tough nut (to crack)
: a person or thing that is difficult to deal with, understand, or influence
▪ The team's defense is a tough nut to crack. ▪ The problem is a hard nut to crack. ▪ He's a tough nut, but I think I can get him to agree to the contract.
▪ The team's defense is a tough nut to crack. ▪ The problem is a hard nut to crack. ▪ He's a tough nut, but I think I can get him to agree to the contract.
nuts and bolts
: the basic parts or details of an activity, job, etc.
▪ She's still learning the nuts and bolts of the business. ▪ Tell me what the nuts and bolts of the plan involve.
▪ She's still learning the nuts and bolts of the business. ▪ Tell me what the nuts and bolts of the plan involve.
soup to nuts — see 1soup
— nut·like /ˈnʌtˌlaɪk/ adjective [more nutlike; most nutlike]
▪ The cake had a nutlike [=nutty] taste.
/ˈnʌtˌlaɪk/ adjective [more nutlike; most nutlike] ▪ The cake had a nutlike [=nutty] taste.
