of a concept or idea not associated with any specific instance
or more rarely:
describing someone as distracted -- thinking about something outside of the immediate conversation or circumstances
After they had examined the figure, and had walked on finishing their dispute, they had parted, Ladislaw lingering behind while Naumann had gone into the Hall of Statues where he again saw Dorothea, and saw her in that brooding abstraction which made her pose remarkable.
Will Ladislaw was stretched on the rug contemplating the curtain-pole abstractedly, and humming very low the notes of "When first I saw thy face;" while the house spaniel, also stretched out with small choice of room, looked from between his paws at the usurper of the rug with silent but strong objection.
There are no more uses of "abstract" identified with this meaning, but check unspecified meaning below.
Show samples from other sources
We all agree that we want what’s "best for the country", but that is an abstract concept and we cannot agree on which specific laws should be passed.
They say, when he was a little boy, he made an abstract of ’Hop o’ my Thumb,’ and he has been making abstracts ever since.
These irregularities of judgment, I imagine, are found even in riper minds than Mary Garth’s: our impartiality is kept for abstract merit and demerit, which none of us ever saw.
The result of all was so far from displeasing to Mr. Casaubon, that he arranged for the purchase of the picture in which Saint Thomas Aquinas sat among the doctors of the Church in a disputation too abstract to be represented, but listened to with more or less attention by an audience above.
She attributed Dorothea’s abstracted manner, and the evidence of further crying since they had got home, to the temper she had been in about Sir James Chettam and the buildings, and was careful not to give further offence: having once said what she wanted to say, Celia had no disposition to recur to disagreeable subjects.
And now within all the automatic succession of theoretic phrases—distinct and inmost as the shiver and the ache of oncoming fever when we are discussing abstract pain, was the forecast of disgrace in the presence of his neighbors and of his own wife.
…English and Swiss Puritanism, fed on meagre Protestant histories and on art chiefly of the hand-screen sort; a girl whose ardent nature turned all her small allowance of knowledge into principles, fusing her actions into their mould, and whose quick emotions gave the most abstract things the quality of a pleasure or a pain; a girl who had lately become a wife, and from the enthusiastic acceptance of untried duty found herself plunged in tumultuous preoccupation with her personal lot.