The English word pronounced /of/ is the noun oaf, a pejorative term for a stupid, uncultured, or clumsy person.
The English preposition of is pronounced /ʌv/, /əv/, or /ə/ depending on where it’s used.
The first of those is the least common because that is a stressed vowel but the word is almost never stressed the way it might be in a spoken list of actual words like to, from, of, about. This gives it the same sound as heard in the words love, dove, glove, where those all start with consonants but end with the strong pronunciation of of: /lʌv/, /dʌv/, /glʌv/.
The second of those with the unstressed schwa is the most common. Use /əv/ in most situations.
Nonetheless the third is hardly rare. It naturally occurs in all but the very most precise and deliberate of elocutions. Most spoken instances of of are actually this lone /ə/. If you were playing cards and someone mentioned that they had a six of clubs, that would come out just like the clock-time six o’clock is pronounced, save for the /lʌbz/ part at the end of the card. It’s common in any XXX of the ZZZ type of construction as well as in a lot of XXX or in a bunch of XXX ones. You’re left with nothing but a weak and barely distinguishable /ə/; hence the eye-dialect spelling of lotta sometimes seen in phrases like “a whole lotta love”