What rule applies to the word avail?

The Word "avail" is typically used as a verb meaning to make use of or benefit from something. It is often followed by the preposition "oneself," as in "to avail oneself of an opportunity." Additionally, when used in the phrase "to no avail," it indicates that an effort was unsuccessful. It's important to note that "avail" can also function as a noun, referring to the benefit or advantage gained from something.