Phrase. to be (or stand) onor upon one's behaviour,or one's good behaviour: to be placed on a trial of conduct or deportment, to be in a situation…

to keep one's nose clean: to behave properly, to keep out of trouble (see also quot. 1909).

to put up a good (also decent,etc.) show: to do well, make a good effort, give a good account of oneself (esp. in a sporting contest). Similarly to pu…