Here are the odd ones out for each set:

1. **a. compass** (it's an object, while the others are subjects)
2. **b. Play** (it’s an action while the others are subjects)
3. **a. have** (it's a verb, while the others are nouns)
4. **b. post office** (it’s a place, while the others are related to school/classroom vocabulary)
5. **d. judo** (it's a sport, while the others relate to school subjects)

Let me know if you need further help!