obstructer vs barrier

obstructer and barrier both are nouns.

Word	Noun	Adjective	Verb	Adverb
obstructer	Yes	No	No	No
barrier	Yes	No	No	No

As nouns, barrier is a hyponym of obstructer; that is, barrier is a word with a more specific, narrower meaning than obstructer:

obstructer (noun)	barrier (noun)
any structure that makes progress difficult	a structure or object that impedes free movement
someone who systematically obstructs some action that others want to take	any condition that makes it difficult to make progress or to achieve an objective
	anything serving to maintain separation by obstructing vision or access