Ensures there are no strings attached?

• Anagram and antonym of "unites"
• Frees from Matthew Walker
• Renders knotless
• Looses
• Removes, as a knot
• Loosens, as laces
• Reduces a knot to naught, say
• Sets loose

Wiktionary Word definitions in Wiktionary
vb. (en-third-person singular of: untie )