I have noticed a lot of people use of instead of have, for example: "that must of been really annoying". Is this correct?

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    I hope you don't mean that. It could also be a sign of newness to English.
    – Daniel
    Commented Sep 25, 2011 at 23:34
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    @drɱ65δ: I read ear-literate as an eggcorn of illiterate…
    – Jon Purdy
    Commented Sep 26, 2011 at 2:58
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    It will shock many to learn that the OED has an entry for the verb ‘of’. Its etymology is given as ‘variant of HAVE (verb), arising through misapprehension of the verb (when occurring as a clitic) as showing OF (prepostion)’ and it is described as non-standard. The entry has ten citations from 1814 to 1998, including one from the surely far from idiotic Charlotte Brontë. Commented Sep 26, 2011 at 6:26
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    @drɱ65 δ: Newness to English? Really? I learned English as a second language, and I don't think anyone who has painstakingly learnt "I should have" and "that must have" would make this particular mistake. Instead, I see this as a rather sure sign of a native English speaker. Commented Sep 26, 2011 at 8:26
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    I believe you, not knowing much about the subject myself - but I still think idiot is too strong a term. Even lazy could be unfounded.
    – Daniel
    Commented Sep 26, 2011 at 12:07

1 Answer 1


In speech, this is merely a relaxation of pronunciation - should have becomes should've, must have becomes must've. This relaxed pronunciation is fine.

However, the contracted have (i.e. -ve) should not be written as of. Of sounds similar to -ve, so many people erroneously think should of and must of is how to write should've and must've. Should of and must of are improper.

Use should have and must have when you are writing, unless you are writing dialogue, or writing informally. In those cases you also have the option of using the contractions should've and must've:

That must have been really annoying.

Or, in dialogue and informal settings (e.g. chat):

"That must've been really annoying!" said Jack.

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    Originally it must have been a "mere relaxation of pronunciation", but more recently I've heard people say "must of" etc. very clearly (i.e. the sound must be "of" and can't possibly be "'ve"). Misapprehension feeding back upon itself, I suppose... Commented Sep 26, 2011 at 8:26
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    It's a legitimate spoken clitic, just like shortening "I am going to go to the store" to "I'm'ina go to the store." It has no corresponding written form. It's usually pronounced like "must'a". Commented Mar 19, 2012 at 22:37
  • I think "of" and "'ve" are homonyms, so I don't see how one could "very clearly" say "must of" as Karl claims. Commented Jan 23, 2014 at 5:36
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    @KefSchecter, "of" has two (or more) common pronunciations depending on whether it's stressed or not. If it's stressed, it often sounds completely different from its unstressed form which is the homophone of "'ve". So perhaps that's what Karl meant, that the person clearly said the stressed pronunciation and thus likely meant "of". For example, US pronunciation of stressed vs unstressed: /ʌv/ vs /əv/, /ə/.
    – Kasenjo
    Commented Jun 6, 2016 at 11:46

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