Definition of vail in English:

vail

verb

[with object]archaic
  • 1Take off or lower (one's hat or crown) as a token of respect or submission.

    • ‘He vailed his bonnet to no one but a judge.’
    • ‘Turning himself towards the noblemen that sat on a form placed before the scaffold, he vailed his hat.’
    • ‘Vailing his cap, like them, to the Queen's representatives, he covered himself when he looked at the Pope's delegate.’
    1. 1.1no object Take off one's hat or otherwise show respect or submission to someone.

Origin

Middle English (originally in the sense ‘lower (one's eyes, weapon, banner, etc.) as a sign of submission’): shortening of obsolete avale, from Old French avaler ‘to lower’, from a val ‘down’ (literally ‘in the valley’).

Pronunciation

vail

/veɪl/