also: さみしがりや
noun
lonely person; person who hates being alone
Describes someone who easily feels lonely and seeks company. Often used in a slightly self-deprecating or affectionate way.
彼は寂しがり屋で、いつも誰かと一緒にいたがる。
He's a lonely person and always wants to be with someone.
うちの猫は寂しがり屋で、
Our cat hates being alone and comes to me as soon as I get home.