If you know that sluggish means slow-moving, then you have a clue to the meaning of sluggard. A sluggard is a lazy, sleepy, slow-moving person.
A sluggard is likely to oversleep and even snooze through class or work. If you’re alert and hard-working, no one will ever call you a sluggard or a slug. Being a sluggard is a great way to fail a class, lose a job, or just fall behind in general. Ex:
-I’m waiting for those sluggards to bring my steak.
-How long will you lie there, you sluggard? When will you get up from your sleep?