Related Clues:

• "The ___ Duckling" (fairy tale)
• It's not nice starting university with key to empty place
• Unblocking lavatory - when emptied it ain't pretty
• Turn ___ (become unpleasant)
• Threatening, disquieting
• __ Betty, US comedy-drama series
• Disheartened lurgy turned nasty
• Lastly, you mentioning occupational injury is threatening
• ___ truth (uncomfortable reality)
• Unpleasant to the eye
• Horrible-looking fruit, I hear
• Not pretty at all
• Likely to turn violent
• Not looking good, using library, overlooking contents
• Like many Christmas sweaters