The manner in which we speak and write are part of how we are evaluated in terms of professionalism. Here are a few phrases you don't want to use as such, whether online or off:
Want to start off your day with a bang and grammatically correctly at the same time? Get an espresso. The word "expresso" doesn't exist.
Correct usage: "I'll take a triple espresso. This is going to be the best pitch ever."
2. Scotch free/Scott free
Getting off scot-free means getting away with something without punishment or consequences. Many believe it comes from the 16th century, when a tax or fee was known as a "scot." Thus this example from John Wolcot's Odes of Condolence: "Scot-free the Poets drank and ate; They paid no taxes to the State!"
Correct usage: "Looks like that street artist got away scot-free again."
3. Statue of limitations
A statue is a trophy or other physical item; a statute is a legal term. A statute of limitations refers to the time limit on prosecuting a certain crime. For example, the statute of limitations in California for professional malpractice is 1 year from discovery. You can only prosecute if it's within a one-year window from when you found out about the malpractice.
Correct usage: "There is no statute of limitations for murder."
4. Nip it in the butt
The correct phrase here is "nip it in the bud," and it comes from gardening. When you nip something in the bud, it means you stop it before it gets the chance to flower. Nipping something in the butt is meaningless unless you're a sheepdog.
Correct usage: "He texted you again? You'd better nip that in the bud."
5. Flush out
I've seen this in emails before and winced. If you want to say you're expanding on an idea, you're fleshing it out, not flushing it out. It comes from drawing, when you would outline the skeleton of a person first, then add flesh.
Correct usage: "Let's flesh out this idea at the meeting."
6. On accident
Prepositions are the bane of existence for more than just middle schoolers - even adults misuse them. The correct phrase here is always "by accident." You can do something on purpose, but you can't do it on accident.
Correct usage: "I think Kenda sent us that Slack message by accident."
7. I could care less
This is my personal pet peeve. When you say you could care less, it means you do care - at least a bit. If you want to express that you really don't care at all, you must say "I couldn't care less."
Correct usage: "I couldn't care less whether we paint the conference room pink."
Good luck following all the rules of grammar. May you always get things right, or if you get them wrong, may you get away scot-free.