1.
one-time; one-shot; standalone
Something that occurs only once or is not part of a series. Used for events, jobs, broadcasts, and other activities that are not recurring.
単発のアルバイトを探している。
I'm looking for a one-time part-time job.
このドラマは連続ではなく単発だ。
This drama is a standalone, not a series.
単発のイベントだったが、好評で定期開催になった。
It was a one-time event, but it was well received and became a regular event.
2.
single-engine; single-shot
In technical contexts, having only one engine (aircraft) or firing one shot at a time (firearms).
単発エンジンの小型機が着陸した。
A small single-engine aircraft landed.
この銃は単発で、一発ずつ装填する必要がある。
This gun is single-shot and needs to be loaded one round at a time.
単発の飛行機は双発機より燃費がいい。
Single-engine planes have better fuel efficiency than twin-engine ones.
Composed of 単 (single) and 発 (emission, shot). Sense 1 is far more common in everyday use.
COMMON COLLOCATIONS:
- 単発の仕事: one-time job
- 単発ドラマ: standalone TV drama (not a series)
- 単発のイベント: one-off event
- 単発講座: single-session course
OPPOSITE:
- 連続: serial, continuous — the opposite of one-time
- 連載: serialized — for publications
SIMILAR WORDS:
- 一回限り: one time only — emphasizes the limit
- 一度きり: only once — more emotional/emphatic