1. (

• by_chance ,
• accidentally ,
• circumstantially ,
• unexpectedly

) without advance planning; "they met accidentally" ;

2. (

• incidentally ,
• accidentally ,

) of a minor or subordinate nature; "these magnificent achievements were only incidentally influenced by Oriental models" ;

3. (

• unintentionally ,
• accidentally ,

) without intention; in an unintentional manner; "she hit him unintentionally" ;