Source : Webster's Revised Unabridged Dictionary (1913)

Ail \Ail\ ([=a]l), v. t. [imp. & p. p. {Ailed} ([=a]ld); p. pr.
   & vb. n. {Ailing}.] [OE. eilen, ailen, AS. eglan to trouble,
   pain; akin to Goth. us-agljan to distress, agls troublesome,
   irksome, aglo, aglitha, pain, and prob. to E. awe. [root]3.]
   To affect with pain or uneasiness, either physical or mental;
   to trouble; to be the matter with; -- used to express some
   uneasiness or affection, whose cause is unknown; as, what
   ails the man? I know not what ails him.

         What aileth thee, Hagar?                 --Gen. xxi.
                                                  17.

   Note: It is never used to express a specific disease. We do
         not say, a fever ails him; but, something ails him.

Ail \Ail\, v. i.
   To be affected with pain or uneasiness of any sort; to be ill
   or indisposed or in trouble.

         When he ails ever so little . . . he is so peevish.
                                                  --Richardson.

Ail \Ail\, n.
   Indisposition or morbid affection.             --Pope.

Source : WordNet®

ail
     n : aromatic bulb used as seasoning [syn: {garlic}]

ail
     v 1: be unwell, ill, or ill disposed
     2: cause bodily suffering to [syn: {afflict}, {trouble}, {pain}]