1. (

• challenge ,
• dispute ,
• gainsay

) take exception to; "She challenged his claims" ;

2. (

• quarrel ,
• dispute ,
• scrap ,
• argufy ,
• altercate

) have a disagreement over something; "We quarreled over the question as to who discovered America"; "These two fellows are always scrapping over something" ;

1. (

• disputed

) subject to disagreement and debate ;