1.
lost child
A child who has become separated from their parents or guardians.
2.
lost person, someone who is lost
By extension, anyone who has lost their way (often used playfully for adults).
It's embarrassing to get lost even though I was looking at a map.
Playful adult usage
迷子 is literally a lost child — the kanji are 迷 'to be lost, confused' and 子 'child.' It is the standard word in announcements and signage at stations, department stores, and festivals.
It is also used freely of adults, usually with a light, self-deprecating tone: an adult who says 迷子になりました is admitting to being thoroughly lost, a little comically. For a serious case — a missing person whose whereabouts are unknown — the word is 行方不明, not 迷子.
Note the grammar: Japanese treats being lost as a state you become, so the verb is なる, not ある or する.
Common collocations
- 迷子になる: to get lost
- 迷子センター: lost-child centre
- 迷子のお知らせ: a lost-child announcement
- 迷子札: an identification tag worn by children at crowded events