A British informal word for someone who looks, or acts, very stupid — not clever-cruel, more empty-headed, as if nobody is home behind the eyes. 'Don't just stand there looking gormless.' It is a bit old-fashioned and comic; a parent or a teacher might say it with a sigh, not as a vicious insult. It comes from a dialect word gaum, meaning heed or attention, plus -less (without): so without attention, without sense. The r in this spelling is not really an extra sound in most British speech; it is an old spelling trick, common in accents that do not pronounce r after a vowel, to show that the vowel is long. American English almost never uses the word.