The Collaborative International Dictionary of English v.0.48:

Welaway \Wel"a*way\, interj. [OE. welaway, walaway, weilawey;
   wei wo! (Icel. vei) + la lo! (AS. l[=a]) + wei wo!; cf. AS.
   w[=a] l[=a] w[=a]. See Woe.]
   Alas! [Obs.]
   [1913 Webster]

         Then welaway, for she undone was clean.  --Wyatt.
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