Source : Webster's Revised Unabridged Dictionary (1913)

Toil \Toil\, v. i. [imp. & p. p. {Toiled}; p. pr. & vb. n.
   {Toiling}.] [OE. toilen to pull about, to toil; of uncertain
   origin; cf. OD. teulen, tuylen, to labor, till, or OF.
   tooillier, toailler, to wash, rub (cf. {Towel}); or perhaps
   ultimately from the same root as E. tug.]
   To exert strength with pain and fatigue of body or mind,
   especially of the body, with efforts of some continuance or
   duration; to labor; to work.

Source : WordNet®

toiling
     adj : doing arduous or unpleasant work; "drudging peasants"; "the
           bent backs of laboring slaves picking cotton"; "toiling
           coal miners in the black deeps" [syn: {drudging}, {laboring},
            {labouring}]