just the two of them; alone together
Describes a situation where only two people are present, often implying intimacy or privacy. Commonly used with で or as an adverbial phrase.
See also: 二人っきり
Let's have dinner just the two of us tonight.
I get nervous when we're alone together in a room.
Standard kanji-kana mixed spelling.
Kanji spelling using 切; less common but still seen.
Variant using numeral 2.
Numeral plus kanji 切; rare.
Compound of 二人 (ふたり, 'two people') + きり (from 切る, 'to cut off'), meaning 'only, just'. The きり part indicates limitation, so the whole means 'limited to two people'.