verb

1. To apply, or apply something to, in a hasty, careless, or rough manner; to roughcast.

   “to slapdash a wall”

adjective

1. Produced or carried out hastily; haphazard; careless.

adverb

1. In a hasty or careless manner.

2. Directly, right there; slap-bang.

   “Van Eyck signed his portrait of the Arnolfinis slapdash in the center of the painting.”

3. With a slap; all at once; slap.

Synonyms: carelessly, haphazardly, hastily, directly