verb

• (transitive) To ponder, to go over in one's mind.
  "Idly, the detective thought what his next move should be."
• (transitive) To have (some statement) in one's mind; to say to oneself mentally.
  ""I should phone my mother," I thought."
• (intransitive) To communicate to oneself in one's mind, to try to find a solution to a problem.
  "I thought for three hours about the problem and still couldn’t find the solution."
• (intransitive) To conceive of something or someone (usually followed by of; infrequently, by on).
  "I tend to think of her as rather ugly."

noun

• (chiefly UK) An act of thinking; consideration (of something).
  "I'll have a think about that and let you know."

verb

• (obsolete except in methinks) To seem, to appear.
  "And whanne syr launcelot sawe he myghte not ryde vp in to the montayne / he there alyghte vnder an Appel tree /[…]/ And then he leid hym doune to slepe / And thenne hym thoughte there came an old man afore hym / the whiche sayd A launcelot of euylle feythe and poure byleue / wherfor is thy wille tourned soo lyghtely toward thy dedely synne"