1. (very) large or significant, sth of consequence
(a) considerable amount/growth/increase
'Considerable' is an adjective that usually refers to the amount of something. If something is considerable in size it usually means it is big or notable. You might have a 'considerable amount' of money or materials, or 'considerable costs' to cover. Often it has a negative connotation but not always. This is an adjective that can be used in social or professional contexts but usually in more formal situations.