methinks (v.) Look up methinks at Dictionary.com
Old English me þyncð "it seems to me," from me (pron.), dative of I, + þyncð, third person singular of þyncan "to seem," reflecting the Old English distinction between þyncan "to seem" and related þencan "to think," which bedevils modern students of the language (see think). The two thinks were constantly confused, then finally merged, in Middle English. Related: Methought.