expression, suru verb (irregular)
be out of the house often; spend little time at home; go out a lot
Idiomatic expression describing a person who is frequently away from home, treating the outside as their main place. Often used to characterize someone's lifestyle.
彼は仕事が忙しくて、最近家を外にしている。
He's been so busy with work lately that he's rarely at home.
大学生になってから、すっかり家を外にするようになった。
Since becoming a university student, I've started spending very little time at home.