1. unsubstantiate - Adjective
2. unsubstantiate - Verb
To prove false; to disprove or discredit.
(human services) To officially categorize (an allegation) as unsubstantiated.
To call into question; to create doubt about.
To make insubstantial or abstract; unsubstantialize.
Lacking substance; insubstantial.
Unsubstantiated; unproven.
Source: en.wiktionary.org