On-the-spot and On the spot

On-the-spot adjective - At the scene of action.

On the spot and on-the-spot are semantically related In some cases you can use "On the spot" instead the phrase "On-the-spot" as an adjective or an adverb.

On the spot adverb - At the place in question; there.

On-the-spot and on the spot are semantically related in fast topic. Sometimes you can use "On-the-spot" instead the phrase "On the spot" as an adjective or an adverb, if it concerns topics such as immediate, extemporaneous, unrehearsed, improvised.