1. Trial; temptation 
2. A mode of adjusting or operating by repeated trials or experiments

Derived forms: tentations

• unappreciative
• unappreciatively
• unapprehensive
• unapproachability
• unapproachable
• unappropriated
• unapproved
• unapt
• unarbitrary
• unarguable
• unarguably
• unargumentative
• unarm
• unarmed
• unarmored
• unarmoured
• unarticulate
• unarticulated
• unartistic
• unary
• unary operation
• unascertainable
• unascribable
• unashamed
• unashamedly