Comparative form of 'brashy,' meaning more resembling or having more of the quality of brash/rash material or behavior.
From brashy (meaning resembling brash, or made of brash material) plus the comparative suffix '-er.' Brashy itself relates to brash through adjectival formation.
Words like 'brashier' show how English can keep adding suffixes to create new forms, though the deeper you go (like 'brashier' vs. 'brasher'), the more obscure and rarely-used it becomes.
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