A person who tends to find things bothersome and is unwilling to put in effort; a lazy/reluctant-to-do-things person (colloquial).
彼はめんどくさがり屋だから、部屋の片付けはいつも後回しにする。
He's lazy about chores, so he always puts off tidying his room.
めんどくさがりやの友達と一緒だと、計画を立てるのが大変だ。
It's hard to make plans when I'm with a friend who's a bother-avoidant (a 'mendokusagariya').
掃除が面倒で、ついついめんどくさがり屋な自分が出てしまう。
Cleaning is such a hassle that my lazy side inevitably comes out.