Look them up here. You'll find examples of their use in context.
Interested in Language
What's the biggest difference between those two words and in what different context you would use them ?
so basically e.g. scruffy t-shirt is messy and dirty but shabby is old, worn-out. Is that true ?
What about houses ? Does the same rule apply ?
I would use scruffy for hair, general appearance etc. I would use shabby for furniture, décor, paintwork, general state of repair of a building.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.