While one of the concerns of this blog is finding obscure yoji that will wow onlookers and require a bit of reading into Chinese history, we also realize that sometimes you just want the yoji without all the smoke and mirrors. In that situation, this is the yoji for you.
1. Cutting to the chase
2. To speak clearly and frankly
3. Get to the point
To 単刀直入, the origin of the phrase is revealed in the breakdown of the kanji. You just grab a single sword and charge the enemy, because really, what else is there to discuss?
One would do well to note that one should be careful when using it with superiors. That's not to say that you can't use it at all, but that when using it you have to deploy it with all the 敬語 trimmings if you don't want to seem like a disrespectful, ungrateful oaf. The best use, perhaps, is in preceding a plain-spoken point you're preparing to make to a friend that might come off as unnecessarily brusque otherwise. That can be useful in a second language since you're not always able to garnish dialogue with all the nuances you would otherwise employ, and throwing out a 単刀直入 can make that lack of filler seem more intentional, and thus AWESOME.
Since I'm honestly a little conflicted about lingering on about a phrase that expressly demands I do the opposite, it might be appropriate to arm you with the other side of this idea: 遠回し(toomawashi). The meaning of this one? You guessed it - beating around the bush, or approaching something in an indirect manner. The expression listed above is a little rough to fit into conversation, so try 遠回しに, as in 「遠回しに言うな、お前！」, or...
The vice principal is always speaking to me in this round-about way. It would be better if he could just get to the point.
See what I did there?