From nut +‎ -y.

• (Received Pronunciation, General American) IPA^(key): /ˈnʌti/

• Audio (Southern England):

  (file)

• Rhymes: -ʌti
• Hyphenation: nut‧ty

nutty (comparative nuttier, superlative nuttiest)

2. Containing nuts.

   This is a nutty chocolate bar.

4. Resembling or characteristic of nuts.

   Synonyms: (resembling or characteristic) nuttish; (resembling) nutlike

   • 1997, Mary Jo Plutt, Prevention's Stop Dieting and Lose Weight Cookbook, Rodale, →ISBN, page 210:

     Brown rice has had only its outer hull removed, leaving it with a beige color and a pleasantly nutty flavor.

   • 2016 December 16, Peter Shadbolt, “What does a $22,000 cognac actually taste like?”, in CNN‎^[1]:

     David Mason, Beverage and Bar Manager at St. Regis, describes the complex aromas and layered palate of the cognac thus: “It’s kind of autumn flavors. Really nutty, almondy – kind of fig, plum, dried fruits. But it finishes off really smoothly but with a little bit of tobacco leaf.”

6. (slang) Barmy: eccentric, odd; crazy, mad, insane.

   Synonym: squirrelly

   Near-synonyms: nuts; see also Thesaurus:insane

   That student's parents seem to be nutty as a fruitcake.

8. (UK, Ireland, dated) Extravagantly fashionable.
   • 1932, Frank Richards, “The Complete Outsider”, in The Magnet:

     Skinner's friendship with his nutty pals seemed to have come to a sudden end.

• In the sense of “insane”, similar to nuts, but more limited and somewhat milder: nutty means “eccentric, insane”, while “nuts” can mean either “insane, crazy” or “excited, enthused”, for example in the phrase “the crowd went nuts”, the other term, “the crowd went nutty”, is not used.

• coconutty, coco-nutty
• nutter