The term 'became threadbare' can be broken down into two crossword solutions: 'WORE' (4 letters) and 'WOREOUT' (7 letters). Wore is a verb meaning to have clothing on one's body, while woreout is an adjective meaning to have been used so much that it is no longer useful. Together, these two words describe the process of something becoming threadbare, which is when an item of clothing has been used so much that it is no longer in good condition.