Reefer/ˈriːfər/ Definition 1 of 3Pro Tip 1/3Upper Body Specifically refers to a jacket for the torso, much like a blazer or pea coat. The cold wind made me glad I was wearing my reefer. Pro Tip 2/3Outdoor Wear Typically worn for warmth outside, not usually an indoor garment. She grabbed her reefer before leaving for the autumn evening. Pro Tip 3/3Stylish History Originally a naval term, now fashionable, it may connote a classic or vintage style. His reefer gave his outfit a nautical twist.