minesomine asks: When do you use "off" versus "of", and how do you remember the difference?

With examples from The Dresden Files


The words off and of are similar, yet very different, and are easily confused with each other. Off, according to Dictionary.com has a variety of meanings, but it is basically an adverb (and sometimes a preposition) that is used to indicate that something is away from a place or time; or when something is removed; or even as a reference to the opposite of the word, on.

"If you need to take off and head home," Thomas said with a look of indifference, "Feel free."

"Take off the coat, child," Godmother said airily. "It does not suit you."

The lights were suddenly turned off, and darkness seemed to fill every nook and cranny. I gave Murphy a little push and shouted for her to move.

Of, on the other hand is a preposition that is used to indicate distance or direction from; relationship or possession between two things; or a point of origin/source, among other meanings.

We were within sight of the Water Beetle, when a huge, gray cloud erupted over the craft. "What the..." was all I was able to say before all hell broke loose.

"Ugh," Molly said as she shielded her eyes against the glare that bounced off the surface of the countertop. "Harry? What's happening?"

"We are a product of our mother," Thomas said wearily. "It had to go this way."

Of course, there are times when both words can be used together, such as:

We worked off of each other in a way that seemed to imitate a well-oiled machine.

Off of is an idiom, or informal use for the word off, and while it is still a popular phrase, it is considered redundant in various usage guides. If it is necessary for a character to use this phrase in your fiction, it's important to make sure they are in the correct context.

Remembering which one to use will hopefully be easier now that we have a good understanding of the way each is used, but here's a more compact way to remember it: One F if the word pertains to belonging to someone or something; and two if the word indicates being away from, or is removed.