Source : Webster's Revised Unabridged Dictionary (1913)

Oily \Oil"y\, a. [Compar. {Oilier}; superl. {Oiliest}.]
   1. Consisting of oil; containing oil; having the nature or
      qualities of oil; unctuous; oleaginous; as, oily matter or
      substance. --Bacon.

   2. Covered with oil; greasy; hence, resembling oil; as, an
      oily appearance.

   3. Smoothly subservient; supple; compliant; plausible;
      insinuating. ``This oily rascal.'' --Shak.

            His oily compliance in all alterations. --Fuller.

   {Oily grain} (Bot.), the sesame.

   {Oily palm}, the oil palm.

Source : WordNet®

oily
     adj 1: containing an unusual amount of grease or oil; "greasy
            hamburgers"; "oily fried potatoes"; "oleaginous seeds"
            [syn: {greasy}, {sebaceous}, {oleaginous}]
     2: unpleasantly and excessively suave or ingratiating in manner
        or speech; "buttery praise"; "gave him a fulsome
        introduction"; "an oily sycophantic press agent";
        "oleaginous hypocrisy"; "smarmy self-importance"; "the
        unctuous Uriah Heep" [syn: {buttery}, {fulsome}, {oleaginous},
         {smarmy}, {unctuous}]
     3: coated or covered with oil; "oily puddles in the streets"
     4: smeared or soiled with grease or oil; "greasy coveralls";
        "get rid of rubbish and oily rags" [syn: {greasy}]
     [also: {oiliest}, {oilier}]

oilier
     See {oily}