1. Unwisely talking too much
   - bigmouthed, blabbermouthed, talkative

See also: indiscreet

• unilluminating
• unilocular
• unimaginable
• unimaginably
• unimaginative
• unimaginatively
• unimagined
• unimitable
• unimodal
• unimpaired
• unimpassioned
• unimpeachable
• unimpeachably
• unimpeded
• unimportance
• unimportant
• unimposing
• unimpregnated
• unimpressed
• unimpressionable
• unimpressive
• unimpressively
• unimprisoned
• unimproved
• unincorporated