Jingo
/ˈdʒɪŋɡəʊ/
Definition 1 of 2
Pro Tip 1/3Negative Connotation
Often used to criticize someone's excessive patriotism, implying it's unreasonable or aggressive. 
The debate turned tense when Mark was labeled a jingo for his extreme views.
Pro Tip 2/3Political Usage
Common in political discussions to describe those favoring military action. 
During the election, the candidate's jingo stance became a hot topic.
Pro Tip 3/3Caution with Usage
Use carefully; calling someone a jingo can be offensive and provoke an argument. 
I wouldn't openly call him a jingo unless you're ready for a heated debate.