Second Lieutenant, Ensign
noun
Someone who's only been a military officer for a few years hasn't been able to get very far in the ranks. They're an ensign, or a second lieutenant. That's still not a bad position to be in!
しょうい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
私の曽祖父は、旧日本陸軍少尉でした。
My great-grandfather was a second lieutenant in the former Japanese army.