substantial
adjective
uk/səbˈstænʃəl/ uslarge in size, value, or importance:
substantial benefits/costs/investment
a substantial amount/number/portion of sth Banks make a substantial amount of money investing your money.
substantial changes/differences/improvements We've made substantial changes in how we go about doing our business.
a substantial increase/reduction/rise in sth The company posted a substantial increase in profits during the year to £3.5m.
[ before noun ] formal
relating to the main or most important things being considered:
Unions and bosses reached substantial agreement.