expression
A polite set phrase said when leaving home or a place, implying you will return. The typical response is いってらっしゃい.
See also: 行ってらっしゃい
「行ってきます！」「行ってらっしゃい。」
"I'm off!" "See you later."
学校に行ってきます。
I'm off to school.
The standard response to 行ってきます, said to someone leaving.
Said upon returning home; the counterpart to 行ってきます.
From the te-form of 行く (iku, 'to go') + 来る (kuru, 'to come') in polite form, literally 'I go and come back'.