"stupid behaviour" is correct and usable in written English.
It is often used to describe an action or attitude that lacks common sense or intelligence. For example, "His stupid behaviour almost caused a major accident."
They treated hoaxes with solemnity, and turned ill-fame and stupid behaviour into lucrative commodities.
Both Chris and Nick's stupid behaviour really has an effect on Maddie.
So I wasn't the only one who thought this gaggle plus their "militant" (their words, not mine) mates were needlessly upsetting people with their stupid behaviour.
"This shows a huge lack of respect to us as Malaysians; this is stupid behaviour from foreigners who have no sense of cultural sensitivity and respect," Razlan said.
The research showed that the students believed there were three main categories of stupid behaviour, with incidents rated more stupid where the consequences were more serious, and where the perpetrator was in a greater position of responsibility.
John Coates at Cambridge's Judge Business School produced some fascinating analysis last year of testosterone and cortisol among City traders and showed how their abnormally high hormones resulted in increasingly risky, and ultimately stupid, behaviour.
"These results bring us closer to understanding people's conception of unintelligent behaviour while emphasising the broader psychological perspectives of studying the attribute of stupid in everyday life".
Excessive, stupid, immature behaviour and that's it".
Stupid animalistic behaviour almost fucked up the Mitchell Brothers' career.
In the latest escalation, O'Connor used Facebook to accuse Cyrus of "stupid and dangerous" behaviour and threatened to take legal action against the US star if she does not apologise publicly or remove the tweets.
Mr Flowers issues an apology for "stupid and wrong" behaviour, saying he has been under pressure because of the bank's problems and a recent death in his family.
