“That’s you done, my dear.”
-- Madam Malkin (PS5)
Madam Malkin was the proprietor of a robe shop in Diagon Alley called Madam Malkin’s Robes for All Occasions. She was a squat witch who was generally very friendly (PS5), though she became alarmed when wands were drawn in her shop (HBP6).
Description of Madam Malkin: “Madam Malkin was a squat, smiling witch dressed all in mauve." (PS5)
Quotes:
“Hogwarts, dear?” she said, when Harry started to speak. “Got the lot here — another young man being fitted up just now, in fact.” - Madam Malkin (PS5)
“But before Harry could answer, Madam Malkin said, 'That’s you done, my dear,' and Harry, not sorry for an excuse to stop talking to the boy, hopped down from the footstool.” (PS5)
“...and as his school robes were now several inches too short in the arm and leg, he visited Madam Malkin’s Robes for All Occasions and bought new ones.” (PA4)
“I think we’d better do Madam Malkin’s first, Hermione wants new dress robes, and Ron’s showing much too much ankle in his school robes, and you must need new ones too, Harry, you’ve grown so much — come on, everyone —” - Molly Weasley (HBP6)
“I don’t think there’s any need for language like that!” said Madam Malkin, scurrying out from behind the clothes rack holding a tape measure and a wand. “And I don’t want wands drawn in my shop either!” she added hastily, for a glance toward the door had shown her Harry and Ron both standing there with their wands out and pointing at Malfoy.” - Madam Malkin (HBP6)
Skills
Seamstress
Robe-fitting
Commentary
Etymology
"Malkin" = the sense most familiar to most readers would probably be that of "cat", with Dark Magic overtones, thanks to Shakespeare's Macbeth ("grimalkin" or "greymalkin"). However, other senses of the word are "a bundle of rags used for cleaning" and "an untidy woman" [NSOED], very ironic for a woman running an outfitter's doing well enough to maintain a shop in Diagon Alley.