string up vs halter

string up is not a noun while halter is a noun.

Word	Noun	Adjective	Verb	Adverb
string up	No	No	Yes	No
halter	Yes	No	Yes	No

As verbs, halter is a hyponym of string up; that is, halter is a word with a more specific, narrower meaning than string up:

Other hyponyms of string up include gibbet.

string up (noun)	halter (noun)
	either of the rudimentary hind wings of dipterous insects; used for maintaining equilibrium during flight
	a woman's top that fastens behind the back and neck leaving the back and arms uncovered
	rope or canvas headgear for a horse, with a rope for leading
	a rope that is used by a hangman to execute persons who have been condemned to death by hanging

string up (verb)	halter (verb)
add as if on a string	prevent the progress or free movement of
kill by hanging	hang with a halter