noun, verbal noun
If you stab and pierce something, you’d better do it in a rush. If you aren't quick enough, you could get into trouble, so rush forth with a mighty charge.
突貫 means doing something in a rush. It’s usually used in the compound 突貫工事, which means fast but often sloppy construction work. It can also describe charging at an enemy, but that meaning is less common today.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
We built the doghouse by constructing it at top speed.