Definition of costful in English:

costful

Pronunciation /ˈkɒs(t)f(ʊ)l/ /ˈkɔːs(t)f(ʊ)l/

adjective

  • 1rare Expensive; sumptuous.

    Apparently not attested in the 17th, 18th, or 19th centuries.

  • 2Involving or characterized by expenditure or loss (of time, effort, etc.); costly. Now somewhat archaic.

    Apparently not attested in the 16th, 17th, or 18th centuries.

Origin

Middle English; earliest use found in Ayenbite of Inwyt. From cost + -ful.