I agree with Andrea on the use of 'clunker.' It's not used all the time, but it's a good colloquialism to know. As for 'snug', the word has a few meanings. Andrea explained its use in regards to being 'warm and cozy.' An example of it being used in relation to tight spaces can be seen below: "The screw was snug." (This would mean the screw was secure in its position.)

I've never heard anyone use the word 'clunker' in relation to a car or anything else. If you want to talk about a car in a disparaging but jocular manner then call it a 'rust bucket' or a 'jalopy' or an 'old banger'. 'Snug' usually has a positive connotation. So I wouldn't tend to talk about a 'snug pair of gloves or pants' because that sounds too uncomfortable for the core idea behind the word. But I would feel snug when lying in bed, wrapped up in my quilt. I might even 'snuggle up' to someone if I were in a good mood. Another meaning of 'snug' in older contexts was a small cubicle in a pub. Some pubs used to have a number of snugs separated from the main bar by curtains, in which you could have a private chat without being drawn into the general merriment. The only place I know of that still has snugs today is the Alehouse (formerly the Hobgoblin) in Reading, Berkshire.

Agree with other replies regarding "snug." You can also use it to talk about clothing that is too tight: "I gained weight and my pants are snug." "I need to buy new shoes; these are snug." "These gloves are snug. I will try the next size up." Also, "snug as a bug in a rug" is one of my favorite expressions :) I don't know why, but it always makes me smile.

Clunkeris mainly with cars.

You can use 'clunker' when talking about cars, but it's considered an insult/joke. And snug is an adjective and verb. You can use snug to talk about tight/close spaces, or to mean 'warm and cozy'. "Look at that old clunker! Surprised it still works." "The mother wrapped the blanket around the child and made sure the child was very snug."