ARISE / RISE
Arise: appear; begin.
e.g. When he was just about to call 911, a few men in uniform arose.
Rise: appear above the horizon; get out of bed.
e.g. The sun rises in the east.
e.g. He rises very early every morning.
RUSTY / RUSTIC
Rusty: corrode (covered with rust); weaken.
e.g. The iron gate has become rusty.
e.g. My grandfather's memory has become rusty.
e.g. Please pardon my rusty French.
Rustic: like the countryside.
e.g. We all enjoyed the rustic views from hilltop.
MEDICATED / MEDICINAL
Medicated: containing medicine.
e.g. Please apply this medicated gauze onto your wound.
Medicinal: having the power to cure.
e.g. He took some medicinal herbs for his cold.
PREVENTABLE / PREVENTIVE
Preventable: can be avoided.
e.g. The accident was preventable if you were more cautious.
e.g. These are preventive measures from head injury.
BULK / HULK
Bulk: in large quantities; the greater part of..
e.g. His business was selling wheat in bulk.
e.g. The billionaire gave the bulk of his estate to charity.
Hulk: a big, clumsy person.
e.g. If you do nothing to your obesity, you will soon become a hulk.