"just for once"
as an exception;
this time, if (or but) at no other time
Related words and phrases:
Two neighbors are talking ...
Neighbor 1: Why do you look so surprised?
Neighbor 2: It's garbage day and our garbage is at the curb. My husband always forgets to take out the garbage.
Neighbor 1: Then you must be pleasantly surprised that just for once your husband actually took out the garbage?
Neighbor 2: I am but I also don't expect it to happen regularly.
Two colleagues are talking ...
Colleague 1: I see the boss is upset again. What did you do this time to upset her?
Colleague 2: Believe it or not, just for once, it wasn't me.
Colleague 1: Well, that is an exception. It's always you that gets into trouble.
There is no gerund form for just for once.
1) Mr. President, do not approve of any portion of this horrible project. Just for once, do something for the right reasons and stand firm.
2) They may well have done a legit poll just for once but when you consider the lack of professional ethics, the deceit and intellectual cowardice ...
3) Let us just for once dwell solely on the positive.
4) Well, tricky Dick tells the truth just for once.
5) The droning air conditioner was silent just for once, the bedroom window open to the cool night.
6) It was simply divine, and just for once I actually tasted some of the cooking I have heard my host family speak so ...
7) I would love to read an article just for once that is not aimed towards the independently wealthy only.
8) The movie basically let Savannah off the hook to have it both ways. Just for once, I was glad when the guy didn't get the girl.
9) I wish just for once that one politician would stand up for our citizens.
10) Tell the truth just for once.
11) Then Mackowski starts singing, and just for once, I'm actually happy about the band having a clean vocalist.
12) You gave it your all, and just for once your all was good enough to placate a boss who fears for his own job ...
13) The storyline is easily the strongest of the first three installments, and just for once Voldemort is not the main villain driving the plot.
14) Please America just for once mind our own business.
15) A truly stunning interview. Just for once all of the truth has been told in less than 20 minutes.
16) ... but I'd wish you'd just listen to me just for once and cut this out.
17) This likely boils down to cost-effectiveness for Big Pharma, but just for once, is also in your interest and favor.
18) Hey, those are within the tolerances! So just for once, an urban legend is correct.
19) It was pathetic. And just for once, I could see that clearly, that's what he was all along.
20) Exactly. Adam babbles but just for once his babbling means something.