Sailor
Noun
へいたい
兵隊ごっこをしているの？面白そう。私も入れてよ。
Are you guys playing soldiers? That looks fun. Let me in too.
A soldier in a squad is a real soldier or sailor, unlike those "soldier" who are not in a squad. They don't have jobs, and can't be called real soldiers.
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.