Our share of the market has decreased sharply this year. We have decreased our involvement in children's books. Decrease means to lower or go down. If you are driving above the speed limit, you should decrease your speed or risk getting a ticket. Students always want teachers to decrease the amount of homework. / dɪˈkriːst / us having become less: decreased costs / sales / spending (Definition of decreased from the Cambridge Business English Dictionary © Cambridge University Press) DECREASED definition: past participle of decrease. and past tense form of decrease. See examples of decreased used in a sentence. Synonyms for DECREASED: dropped, depressed, under, receded, knockdown, low, down, reduced; Antonyms of DECREASED: increased, high, elevated, up, heightened, raised, maximum, extreme Decrease commonly implies a sustained reduction in stages, especially of bulk, size, volume, or quantity, often from some imperceptible cause or inherent process: The swelling decreased daily. decreased Add to list Definitions of decreased adjective made less in size or amount or degree synonyms: reduced The meaning of DECREASE is to become smaller in size, amount, number, or intensity. How to use decrease in a sentence. Synonym Discussion of Decrease. These verbs mean to become smaller or less or to cause something to become smaller or less. decreased simple past and past participle of decrease Derived terms.