At one fell swoop and All together

All together and at one fell swoop are semantically related in together topic. In some cases you can use "All together" instead an adverb phrase "At one fell swoop", when it comes to topics like as a group.

All together adverb - Used of a group whose members acted or were acted upon collectively and when `all' and `together' can be separated by other words.

At one fell swoop and all together are semantically related in together topic. Sometimes you can use "At one fell swoop" instead an adverb phrase "All together", if it concerns topics such as as a group.