Find a spare dry cleaning bag. Place garment on hanger inside the bag and lie flat. Carefully add some activated charcoal or coffee grounds to the bottom opening area. Seal shut with tape. Hang up for a day or two, then air out.
Sort of depends on the origin/nature of the odor without getting too gross. The above method is my go-to for cigarette smoke / food odors (provided not coming from grease or spills directly onto the clothing).