The Collaborative International Dictionary of English v.0.48:

Methinks \Me*thinks"\, v. impers. [imp. Methought.] [AS.
   [thorn]yncan to seem, m[=e] [thorn]ynce[eth], m[=e]
   [thorn][=u]hte, OE. me thinketh, me thoughte; akin to G.
   d["u]nken to seem, denken to think, and E. think. See Me,
   and Think.]
   It seems to me; I think. See Me. [R., except in poetry.]
   [1913 Webster]

         In all ages poets have been had in special reputation,
         and, methinks, not without great cause.  --Spenser.
   [1913 Webster]