also: しぞこなう
godan verb (-u), transitive verb
fail to do; make a mistake in doing; miss doing
Attaches to the continuative form of a verb to express failing to do that action, making a mistake in doing it, or missing the chance to do it. The action is typically intentional but the outcome is unsuccessful.
電車に乗りそこなった。
I missed the train (failed to catch it).
大
I failed to catch the important part (of what was said).