WordWeb Online

1. Large or relatively large in number or amount or extent or degree
   "a considerable quantity"; "the economy was a considerable issue in the campaign"; "went to considerable trouble for us"; "spent a considerable amount of time on the problem"

See also: appreciable, big, goodish, goodly, healthy, hefty, large, respectable, right smart [US, dialect], significant, sizable, sizeable, substantial, tidy [informal]

Antonym: inconsiderable