90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.
The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.
✗ A doctor can’t operate if he doesn’t know the reason of the illness.
✓ A doctor can’t operate if he doesn’t know the reason for the illness.
Other words meaning reason
cause the reason that something happens or that you feel a particular emotion: The probable cause of death was drowning. ♦ Fifty years after the war, scholars still disagree about its causes.
excuse a reason you give in order to explain why you did something bad or wrong: She gave some excuse about being too sick to finish her essay.
explanation a fact or set of facts that tells you why something happened: There was no obvious explanation for his sudden disappearance.
grounds a word used in official or legal situations, meaning a good or fair reason for doing something: His repeated violence toward her was given as grounds for divorce. ♦ Permission for the march was refused, on grounds of public safety.
motivation someone’s personal reason for doing something: The other runners’ times were fast, and that gave me motivation to push even harder.
motive someone’s personal reason for doing something, especially something dishonest or illegal: Police are unsure about a motive for the crime.
pretext a false reason you give for doing something in order to hide your real reason: He got into the warehouse on the pretext of making a building inspection.
purpose the goal that you want to achieve: The purpose of Tuesday’s meeting is to finalize the schedule.