the.com/shabby
The look of clothes that gave up before you did.
means Worn out, run down, or of poor quality — and by extension, dishonorable or unfair behavior.
from From the old English word shab, meaning a scab or a low fellow, itself rooted in scab; by the 1600s the disease metaphor migrated to threadbare coats and threadbare manners alike.
Disease rootsShab once meant a literal skin scab.
Genteel povertyShabby-genteel: broke but desperately keeping up appearances.
Moral senseTreating someone shabbily means meanly, not just messily.