unpersuadable (adj.)

• blind
• cautious
• deaf
• dogmatic
• guarded
• impervious
• incredulous
• inflexible
• leery
• obstinate
• positive
• skeptical
• suspecting
• suspicious
• unimpressionable
• unmovable
• unreceptive
• unresponsive
• unsusceptible
• unyielding
• wary