I. a ‧ vail 1 /əˈveɪl/ BrE AmE noun
to/of no avail if something you do is to no avail or of no avail, you do not succeed in getting what you want:
We searched the whole area but all to no avail. Robbie had disappeared.
II. avail 2 BrE AmE verb
[ Date: 1200-1300 ; Origin: vail 'to be of use' (13-17 centuries) , from Old French valoir ]
avail yourself of something formal to accept an offer or use an opportunity to do something:
How many schools avail themselves of this opportunity each year?