Hawt = A late 1940's and early 1950's acronym for "Having A Wonderful Time."
Now the word is used on the internet as slang for something reeeeally hot.
When British DJ/Presenter Alexa Chung attended the ‘Valentino: Master of Couture’ tribute at the Miu Miu pop-up club in London last week she wore a 1950’s-style Valentino Resort 2013 green satin dress with a cream lace overlay top and black bow belt. Accessorising her outfit with an Anya Hindmarch handbag and a pair of simple black patent Valentino Mary Jane shoes, Alexa looked both lady like and HAWT. This girl just never gets it wrong.