try-hard; person overly conscious about appearing interesting or enlightened
Colloquial, often derogatory term for someone who tries too hard to seem cultured, socially aware, or intellectually superior, especially on social media. Derived from the phrase 意識が高い (having high awareness).
See also: 意識が高い
He's always posting photos of difficult books on social media—a classic try-hard.
Those try-hard students keep going on about startups.
The base phrase meaning 'highly conscious/aware'; 意識高い系 turns this into a label for someone who performs that awareness, often with a negative nuance.
Compound of 意識 (consciousness) + 高い (high) + 系 (type/group). The phrase 意識が高い (to be highly conscious) became a set expression, and adding 系 creates a noun labeling people who exhibit that trait, often with ironic or critical overtones.