It was on his way back past them, clutching a large doughnut in a
bag, that he caught a few words of what they were saying.
Potters, that’s right, that’s what I heard —”
“ — yes, their
son, Harry —”
Mr. Dursley stopped dead. Fear flooded him. He
looked back at the whisperers as if he wanted to say something to
them, but thought better of it.
He dashed back across the road,
hurried up to his office, snapped at his secretary not to disturb him,
seized his telephone, and had almost finished dialing his home number
when he changed his mind. He put the receiver back down and stroked
his mustache, thinkin . . . no, he was being stupid. Potter wasn’t
such an unusual name.
(Harry Potter and the Sorcerer’s Stone)
There is continuous auxiliary + being + adjective structure. In the context, its meaning is, I guess, ‘act foolishly (temporarily)’. Does the structure really have the meaning?
Yes. “He was stupid” would be a general statement about the person: it would mean that that person is a stupid person. “He was being stupid”, in contrast, means that the person was stupid at that point in time, for the duration of a particular action. More precisely, “he was being stupid” means that the person acted stupidly in a particular circumstance. This doesn’t mean (but doesn’t exclude) that he is stupid in general.
You can find the same construction with a lot of adjectives.
When I was doing bad in school, especially at the beginning of 7th grade, she kept asking me if I was being trustworthy, being successful, being smart, not being a slacker. (Robert A. Sullo, Activating the Desire to Learn, 2007)
Chloe is a guest, why are you being such a jerk? (Nicole Knighton, Roommates in New York, 2009)
she’s being either melodramatic or coy (Peter Selgin, 179 Ways to Save a Novel: Matters of Vital Concern to Fiction Writers, 2010)
Source : Link , Question Author : Listenever , Answer Author : Gilles ‘SO- stop being evil’