in a brown study

in a brown study

A state of deep contemplation or rumination, as of a reverie, daydream, or meditation. It originally meant a melancholic or depressed mood or state (dating from at least the 1500s), but has since largely lost that association. Meredith sat at her desk in a brown study, carefully planning how to word her thesis proposal. The would-be poet can often be found in the local café, sequestered in the same corner armchair in a brown study.
See also: brown, study
Farlex Dictionary of Idioms.

brown study, in a

Daydreaming or deeply contemplative, as in Margaret sits in the library, in a brown study. This term dates from the late 1500s, and although by then in a study had long meant "lost in thought," the reason for adding brown is unclear. Moreover, the present idiom also is ambiguous, some holding that it denotes genuine thoughtfulness and others that it signifies absentmindedness.
See also: brown
The American Heritage® Dictionary of Idioms by Christine Ammer.

in a brown study

in a reverie; absorbed in your thoughts.
The earliest meaning of brown in English was simply ‘dark’. From this, an extended sense of ‘gloomy or serious’ developed and it is apparently from this sense that we get the phrase in a brown study .
2001 New York Review of Books When he isn't stirring up mischief, or conniving for gold, or composing beautiful poetry, he's apt to be sunk in a brown study.
See also: brown, study
Farlex Partner Idioms Dictionary
See also:
  • brown study
  • brown study, in a
  • study
  • lap of the gods
  • yellow state
  • in good/poor/etc. state of repair
  • red state
  • regress
  • regress to
  • regress to (something)