send shivers down someone's spine vs unstring

To terrify; to make someone feel extremely nervous. 

To shake the nerves of; to cause anxiety or panic in. 

To defuse or relax. 

To untie. 

To remove from a string; to release something that has been strung up or strung together. 

To split (a text string) into smaller strings by separating on a delimiter. 

To remove the string or strings from.