Which word has multiple meanings

Which word has multiple meanings?

Choose the base word for stars, starfish, starlight

Choose the base word for handmade, handbook, handsaw

Choose the base word for classroom, bedroom, bathroom

Choose the base word for untrustworthy, trusting, trustful

Which word belongs with airfield and airport?

Which word belongs with blur and blurry

Which word belongs with completely and completed?

Which word belongs with washing and washed

Which word belongs with teach and teaching

Which word belongs with writer and written?

Which word belongs with naturally and unnatural?