Definition of if conjunction from the Oxford Advanced Learner's Dictionary



    BrE BrE//ɪf//
    ; NAmE NAmE//ɪf//
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  1. 1  used to say that one thing can, will or might happen or be true, depending on another thing happening or being true If you see him, give him this note. I'll only stay if you offer me more money. If necessary I can come at once. You can stay for the weekend if you like. If anyone calls, tell them I'm not at home. If he improved his IT skills, he'd (= he would) easily get a job. You would know what was going on if you'd (= you had) listened. They would have been here by now if they'd caught the early train. If I was in charge, I'd do things differently. (rather formal) If I were in charge… Even if (= although) you did see someone, you can't be sure it was him.
  2. 2  when; whenever; every time If metal gets hot it expands. She glares at me if I go near her desk.
  3. 3(formal) used with will or would to ask somebody politely to do something If you will sit down for a few moments, I'll tell the manager you're here. If you would care to leave your name, we'll contact you as soon as possible.
  4. 4  used after ask, know, find out, wonder, etc. to introduce one of two or more possibilities synonym whether Do you know if he's married? I wonder if I should wear a coat or not. He couldn't tell if she was laughing or crying. Listen to the tune and see if you can remember the words. Grammar Pointif / whether Both if and whether are used in reporting questions which expect ‘yes’ or ‘no’ as the answer:She asked if/​whether I wanted a drink., although whether sounds more natural with particular verbs such as discuss, consider and decide. When a choice is offered between alternatives, if or whether can be used:We didn’t know if/​whether we should write or phone. In this last type of sentence, whether is usually considered more formal and more suitable for written English.
  5. 5  used after verbs or adjectives expressing feelings I am sorry if I disturbed you. I'd be grateful if you would keep it a secret. Do you mind if I turn the TV off?
  6. 6  used to admit that something is possible, but to say that it is not very important If she has any weakness, it is her Italian. So what if he was late. Who cares?
  7. 7used before an adjective to introduce a contrast He's a good driver, if a little over-confident. We'll only do it once—if at all.
  8. 8  used to ask somebody to listen to your opinion If you ask me, she's too scared to do it. If you think about it, those children must be at school by now. If you remember, Mary was always fond of animals.
  9. 9used before could, may or might to suggest something or to interrupt somebody politely If I may make a suggestion, perhaps we could begin a little earlier next week.
  10. Word OriginOld English gif, of Germanic origin; related to Dutch of and German ob.Idioms used to say something about an event that may or may not happen If and when we ever meet again I hope he remembers what I did for him. used to express an opinion about something, or after a negative statement to suggest that the opposite is true I'd say he was more like his father, if anything. She's not thin—if anything she's on the plump side.  used to give somebody advice If I were you I'd start looking for another job.
    1. 1  used to introduce a different suggestion, after a sentence with if I'll go if you're going. If not (= if you are not) I'd rather stay at home.
    2. 2  used after a yes/no question to say what will or should happen if the answer is ‘no’ Are you ready? If not, I'm going without you. Do you want that cake? If not, I'll have it.
    3. 3used to suggest that something may be even larger, more important, etc. than was first stated They cost thousands if not millions of pounds to build.
     used to say that you wish something was true or that something had happened If only I were rich. If only I knew her name. If only he'd remembered to send that letter. If only I had gone by taxi. used to say that something that is happening is surprising I'm surprised they've invited me to their wedding—it's not as if I know them well. (rather formal) used to state the only situation in which something can happen Only if a teacher has given permission is a student allowed to leave the room. Only if the red light comes on is there any danger to employees.
See the Oxford Advanced American Dictionary entry: if