vague

I guess

I suppose; sure. Often used as an affirmative answer when one is not completely certain or does not want to fully commit. Bob: "You look a little down today. Everything alright?" Mary: "I guess. I've just been feeling vaguely melancholy lately." A: "It's supposed to be sunny today, right?" B: "I guess. I haven't checked the weather."
See also: guess

I guess not

An expression of vague denial or negation. A: "Is Tom coming?" B: "I guess not—it's getting pretty late."
See also: guess, not
Farlex Dictionary of Idioms.

I guess

 and I expect; I suppose; I suspect 
1. a phrase that introduces a supposition. (Frequently, in speech, suppose is reduced to 'spose, and expect and suspect are reduced to 'spect. The apostrophe is not always shown.) Bob: I guess it's going to rain. Bill: Oh, I don't know. Maybe so, maybe not. Alice: I expect you'll be wanting to leave pretty soon. John: Why? It's early yet.
2. a vague way of answering 'yes'. John: You want some more coffee? Jane: I 'spose. Alice: Ready to go? John: I spect.
See also: guess

I guess not.

 and (I) don't think so.; I expect not.; I suppose not.; I suspect not.; I think not.
a vague statement of negation. (More polite or gentle than simply saying no. Frequently, in speech, suppose is reduced to 'spose, and expect and suspect are reduced to 'spect. The apostrophe is not always shown.) Bill: It's almost too late to go to the movie. Shall we try anyway? Mary: I guess not. Tom: Will it rain? Mary: I 'spect not.
See also: guess, not

I guess (so).

 and I believe so.; I expect (so).; I suppose (so).; I suspect (so).; I think so.
a vague expression of assent. (Frequently, in speech, suppose is reduced to 'spose, and expect and suspect are reduced to 'spect. The apostrophe is not always shown.) Tom: Will it rain today? Bob: I suppose so. Sue: Happy? Bill: I 'spect. Sue: You don't sound happy. Bill: I guess not.
See also: guess
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • aint
  • ain't
  • be like ships in the night
  • be like ships that pass in the night
  • be ships that pass in the night
  • not for a second
  • not for a minute
  • not for a moment
  • not for a/one minute/moment/second/instant
  • not for a instant
References in classic literature
At the same time, if we accept the vague datum with which we began, to the effect that, in some sense, there is knowledge of the past, we shall have to find, if we can, such an account of the present occurrence in remembering as will make it not impossible for remembering to give us knowledge of the past.
We sometimes have images that are by no means peculiarly vague, which yet we do not trust--for example, under the influence of fatigue we may see a friend's face vividly and clearly, but horribly distorted.
In this case, as in most others, what may be taken as certain in advance is rather vague. The study of any topic is like the continued observation of an object which is approaching us along a road: what is certain to begin with is the quite vague knowledge that there is SOME object on the road.
The Analysis of Mind
Her first words filled Clayton with vague apprehension.
Tarzan of the Apes
He told the count of his interview with Sila Andreevich (Kochubey spoke of Arakcheev by that nickname with the same vague irony Prince Andrew had noticed in the Minister of War's anteroom).
War and Peace
And before the afternoon was done, they had all managed to enjoy the sweet glory of spreading the fact that pretty soon the town would "hear some- thing." All who got this vague hint were cautioned to "be mum and wait."
They began to feel a vague fear that they had been doing wrong to run away; and next they thought of the stolen meat, and then the real torture came.
Tom Sawyer
From the vague answers to his question how much hay had been cut on the principal meadow, from the hurry of the village elder who had made the division, not asking leave, from the whole tone of the peasant, Levin perceived that there was something wrong in the division of the hay, and made up his mind to drive over himself to look into the matter.
Anna Karenina
But the beginning of things, of a world especially, is necessarily vague, tangled, chaotic, and exceedingly disturbing.
Awakening and Selected Short Stories
"Why not," it said, "buy the petticoat, find out the name of its owner, and, instead of seeking a vague Golden Girl, make up your mind doggedly to find and marry her, or, failing that, carry the petticoat with you, as a sort of Cinderella's slipper, try it on any girl you happen to fancy, and marry her it exactly fits?"
Quest of the Golden Girl
Last night within my chamber's gloom some vague light breath of Spring Came wandering and whispering, and bade my soul take wing.
Lute of Jade
But, I hear you objecting, why is it that these racial memories are not ours as well, seeing that we have a vague other-personality that falls through space while we sleep?
This other-personality is very vague. About the only memory it has is that of falling.
Before Adam
Vague demonstrates that the over-accumulation of private debt does a better job than any other variable of explaining and predicting financial crises.
A Brief History of Doom