The words ‘of’ and ‘off’ are used so frequently in modern English that people often confuse them. For example, the sentence, ‘He took off without a word’ could be mistakenly written as ‘He took of without a word’, and the meaning would be lost. Let us discuss the distinctions between the two words.
The word ‘of’ has several functions, but it is most in use as a preposition that denotes various relations described in the sentence. For instance, it indicates a point of reckoning: ‘South of the border.’ It is also commonly used to point out what something is made of or what it contains: ‘Heart of gold’ (this is metaphorical, of course), ‘Cup of tea’. Another relation frequently described by ‘of’ is that of possession, as in ‘Queen of England.’
‘Off’ is also a very common word with large number of functions as well, but it is most frequently used as an adverb or a preposition. As an adverb, it is used usually to describe a state of discontinuance, or suspension: ‘Turn off the light.’ As a preposition, it is used to indicate the physical separation or distance from a position of rest, attachment or union, as in ‘Take it off the table’ or ‘The gas station is just off the corner ahead.’