what to choose here ?

1) I hate the smell of the disinfectant. ( in a hospital ).

2) He is throwing up / vomiting. ( a nurse to a doctor).

Either one. Vomiting is the medical term.

3) He has a blood clot . ( a nurse to a doctor).
A nurse might know the word coagulum but if you are writing for the public, unless they watch re-runs of ER, they won't.

4) You did that ON purpose.
You did that intentionally

You did that deliberately.

These are all the same.

Thanks Joe.On purpose and a blood clot , you are right.I must be a little precise .

It's not a common thing to say coagulum, but clot sounds more familiar.I think sometimes we must use this medical jargon to clear the way for us .

What about vomit, it's widely used in medical terms.But, we don't use it that much in our daily speaking.Is that right ?