Slap-dash, an adjective used to describe something done carelessly or hastily. Some synonyms for slap-dash are careless, haphazard, reckless, and thoughtless. Another synonym for slap-dash is slovenly, meaning untidy or messy. Other words that can be used in place of slap-dash include clumsy, slap-happy, slapdash, and slipshod. Each of these words suggests an action performed quickly and without thought, resulting in a poor or incomplete outcome. When searching for an alternative to slap-dash, be sure to consider the context of your sentence to ensure that the word you choose fits the tone and meaning of your sentence or paragraph.