1. Characterized by an absence of force or forcefulness
   - undynamic 
2. Lacking strength or vigour
   - asthenic, debilitated, enervated

See also: backward, moribund, stagnant, weak

• impersonal
• impersonality
• impersonally
• impersonate
• impersonation
• impersonator
• impertinence
• impertinent
• impertinently
• imperturbability
• imperturbable
• imperturbableness
• imperturbably
• imperviable
• impervious
• imperviousness
• impetiginous
• impetigo
• impetrate
• impetuosity
• impetuous
• impetuously
• impetuousness
• impetus
• impi