Decisive Action
Perform, Dare, Carry Out
noun, する verb
You use your daring and just go! You made a decisive action by just going like that! It was go or not go and you chose go!
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
本当にこの作戦を敢行するつもりですか。
Do you really intend to carry out this strategy?