WordNet sense 1 (characterized by directness in manner or speech; without subtlety or evasion):

blunt, candid, forthright, frank, plainspoken, point-blank, free-spoken, straight-from-the-shoulder

WordNet sense 2 (extended senses; direct in means or manner or behavior or language or action):

direct

WordNet sense 3 (given to expressing yourself freely or insistently):

vocal

WordNet sense 4 (able or tending to communicate):

communicative, communicatory