Forthink

Origin

From Middle English forthinken, forthynken ("to displease, cause to regret"), corresponding to -("mis-") + think("to seem, appear"), from Old English þyncan ("to seem, appear"); see methinks. Cognate with Middle High German verdunken ("to displease"), Icelandic forþykkja ("to displease"). Compare also Old English forþencan ("to mistrust, despise, despair"), Dutch verdenken ("to suspect"), German verdenken ("to blame").

Full definition of forthink

Verb

1. (transitive, obsolete, impersonal) To cause distress or regret to; cause to regret or repent; to vex.
• 1485, Sir Thomas Malory, Le Morte Darthur, Book II:Sir said Balen me forthynketh of your displeasyr, for this same lady was the untruest lady lyuynge ....
2. (reflexive, obsolete) To regret; repent.
3. (transitive, obsolete) To regret.
• 1485, Sir Thomas Malory, Le Morte Darthur, Book XVII:‘Sir Launcelot, flee and entir nat, for thou ought nat to do hit, for and if thou entir, thou shalt forthynke hit.’
4. (intransitive, obsolete) To repent, be sorry for.
5. (obsolete, transitive) To change one's mind about; to renounce.
• 1596, Edmund Spenser, The Faerie Queene, IV.12:Then gan he thinke, perforce with sword and targe
  Her forth to fetch, and Proteus to constraine;
  But soone he gan such folly to forthinke againe.