Describes something ruffled, unkempt or tousled (hair, bristles, grass, etc.).
寝癖で髪がボサボサになっている。
My hair is all tousled from bedhead.
彼は会うなりボサボサの帽子を脱いだ。
He took off his dishevelled hat as soon as we met.
庭の芝生が手入れされておらず、ボサボサしている。
The lawn hasn't been tended and looks untidy.
Sometimes used to mean idling away time or dawdling — being absent-minded or doing nothing productive.
今日は何もせず家でボサボサして過ごした。
I spent today at home doing nothing and just lazing about.
締め切りが近いのに、彼はボサボサしていて進まない。
Even though the deadline is near, he's dawdling and not making progress.