cud

To contemplate something. ("Cud" is partially digested food that is regurgitated to be chewed again, a common behavior of cows.) I've been chewing my cud for days, but I still haven't decided whether I'm taking the job or not. Sometimes you just need to stop chewing the cud and make a decision.

Fig. to think deeply; to be deeply involved in private thought. (Alludes to the cow's habit of bringing food back from the first stomach into the mouth to chew it, called chewing the cud.) He's chewing his cud about what to do next.

Also, chew over. Ponder over, meditate, as in John tends to chew the cud before he answers, or Let me chew that over and let you know. The first term, first recorded in 1382, transfers the appearance of a patiently ruminating cow to a person deep in thought. The variant was first recorded in 1696.

To ponder over; meditate.

To ruminate, to deliberate over something. For more than four centuries, to chew on something has meant to think it over. Likening human chewing to that of cows and other ruminants, which bring up food in a cud that is chewed and swallowed again, goes back even further. John Wycliffe’s translation of the Book of Hosea (1382) reads, “Thei chewiden cud upon shete, and wyne, and departiden fro me” (7:14); the King James Version (1611) differs (“They assemble themselves for corn and wine, and they rebel against me”). Nevertheless, half a century before that translation was published, chewing the cud in the sense of deep thinking had made its way into a book of homilies (1547).