threadbare
Threadbare (adjective) means Worn so thin that the threads of the fabric show through; shabby from long use. Example: “He answered the door in a threadbare dressing gown.”
How to use threadbare
Learner’s notesIn plain EnglishSo worn out that you can almost see through it — or, for an idea, so overused it has stopped working.
Neutral and slightly literary. In the figurative sense it carries a note of contempt.
It is one word with no hyphen, and it has no comparative form in careful writing — prefer "more threadbare" to "threadbarer".
Trace the full origin ↓Fill the gap
Can you complete this real example?
He answered the door in a _____ dressing gown.
Etymology
From Middle English, literally "bare down to the thread": cloth worn until the nap is gone and only the woven threads remain.