reflect (think) deeply on a subject -- perhaps aloud
’No,’ said Mrs Nickleby, musing.
Ralph Nickleby read this letter twice, and frowning heavily, fell into a fit of musing; the paper fluttered from his hand and dropped upon the floor, but he clasped his fingers, as if he held it still.
He sat, in a musing attitude, for some time, regarding Smike occasionally with an anxious and doubtful glance, which sufficiently showed that he was not very remotely connected with his thoughts.
He smiled and shook his head, and resting his chin upon his hand, fell a musing, and smiled again.
There are no more uses of "muse" identified with this meaning, but check unspecified meaning below.
Show samples from other sources
He mused aloud about the afternoon’s developments.
Let me muse on it on a while and I’ll get back to you.
No. Melt all these down into one, with the three Graces, the nine Muses, and fourteen biscuit-bakers’ daughters from Oxford Street, and make a woman half as lovely.
If I supposed you to be related to Foreign Powers or Native Boards, it is because you have a manner, a carriage, a dignity, which you will excuse my saying that none but yourself (with the single exception perhaps of the tragic muse, when playing extemporaneously on the barrel organ before the East India Company) can parallel.