This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. superlative form of sickly: most sickly.

"Blinded in his right eye just after birth when a midwife rinsed his eyes with a contaminated fluid, Mr. Jordan was the smallest and sickliest of 15 children born to migrant farm worker parents."