Tatty means old, worn out, and not looked after. You use it for things — clothes, furniture, books, buildings — that have been used so long they look shabby: the edges are frayed, the colour has faded, a corner is torn. It is a soft, everyday word, more British than American, and it is not really an insult. If you call your own sofa tatty, you are being a bit fond of it. If you call someone else's coat tatty, you are being a little unkind but not cruel. Note that tatty is about condition, not about dirt: a tatty jumper can be perfectly clean, just worn thin. It is also not about cheapness — an expensive leather bag can go tatty after fifteen years. British speakers often add it to something they still use and half-love: 'my tatty old notebook'. In American English people would more likely say 'ratty' or 'beat-up'.

破舊的、破爛的（衣物、家具用久了變得又舊又醜的樣子，語氣輕，不算重話）