can't rightly say

(I) can't rightly say

I don't know with certainty. A: "How many people are coming to dinner tonight?" B: "I can't rightly say—my family tends to just show up without responding to invitations."
See also: rightly, say

(I) can't rightly say.

Rur. I do not know with any certainty. Fred: When do you think we'll get there? Bill: Can't rightly say. Bob: Okay, how does this look to you? Bill: I can't rightly say. I've never seen anything like it before.
See also: rightly, say
References in classic literature ?
Not knowin' what your notions o' fun may be, I can't rightly say, young feller.
I can't rightly say that raw milk tastes better than the pasteurized product because I don't remember.
I can't rightly say how many readers heeded my call and logged onto ISW or how much traffic ISW generated in its first month of service.
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