To turn to the advantage of.

"I availed myself of the opportunity."

To be of service to.

"Artifices will not avail the sinner in the day of judgment."

To promote; to assist.

To be of use or advantage; to answer or serve the purpose; to have strength, force, or efficacy sufficient to accomplish the object.

"Medicines will not avail to halt the disease."

To provide; to make available.

Effect in achieving a goal or aim; purpose, use

"Any use would probably be an availing of the protection afforded by the passport."

Efficacious.