Signatory, Ratified, Implemented. These and other words making up the jargon of diplomacy mean very different things.

For example:

UNCLOS - "Although the United States helped shape the Convention and its subsequent revisions, and though it signed the 1994 Agreement on Implementation, it has not signed the Convention as it objected to Part XI of the Convention." https://en.wikipedia.org/wiki/List_of_parties_to_the_United_...

UN Convention on the Rights of the Child: "The United States government played an active role in the drafting of the Convention and signed it on 16 February 1995, but has not ratified it" https://en.wikipedia.org/wiki/Convention_on_the_Rights_of_th...

Basel Convention: "Haiti and the United States have signed the Convention but not ratified it." https://en.wikipedia.org/wiki/Basel_Convention