Noun
しゅうぎいん
ある衆議院議員が公費でボートを借りたことが明らかになりました。
It was revealed that a member of the House of Representatives chartered a boat at government expense.
It's the institution that does deliberation on behalf of the populace. They represent the people. They are the house of representatives.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.