Definition of costfully in English:

costfully

adverb

rare
  • Expensively; at a (high) cost; with considerable expenditure (of time, labour, etc.).

Origin

Late Middle English; earliest use found in John Capgrave (1393–1464), prior of Bishop's Lynn, theologian, and historian. From costful + -ly.

Pronunciation

costfully

/ˈkɒs(t)fʊli//ˈkɒs(t)f(ə)li/