hi-tech vs high-tech

hi-tech and high-tech both are adjectives.

Word	Noun	Adjective	Verb	Adverb
hi-tech	No	Yes	No	No
high-tech	No	Yes	No	No

As adjectives, hi-tech and high-tech are synonyms defined as:

hi-tech and high-tech: resembling or making use of highly advanced technology or devices

hi-tech (adjective)	high-tech (adjective)
resembling or making use of highly advanced technology or devices	resembling or making use of highly advanced technology or devices