If I can't become a police officer, I can probably become a security guard even though it's a different job.
この場合、私は discrete という単語は使わず、次のように言います。
ーIf I can't become a police officer, I can probably become a security guard even though it's a different job.
「警察官になれなかったら、多分警備員になれると思うけど、これは別の職業だ」
discreteという単語は日常であまり使う単語ではないです。
discrete を使った例文:
ーHe has discrete spaces in his gallery for all the different types of art in his collection.
「彼のギャラリーには、アートコレクションのタイプ別に個別のスペースがある」
ご参考まで!