Compound of 失くす (to lose) + 物 (thing). The connecting い of the verb stem is dropped.
Common collocations
- 失くし物をする: to lose something
- 失くし物が見つかる: a lost item is found
- 失くし物防止タグ: lost-item prevention tag (e.g., AirTag)
Similar words
- 落とし物: a dropped/found item — emphasis on having been dropped, often found and turned in by others. Lost-and-found offices are 落とし物係, not 失くし物係.
- 忘れ物: a forgotten item — left behind somewhere (in a store, on a train); the owner usually knows where they left it.