1) Associate with 2) Be chummy with 3) Buddy up with 4) Consort 5) Fraternise 6) Socialise 7) Socialize 1) Consort 2) Fraternise 3) Hobnob 
• (v. t.) To bring into fellowship or brotherly sympathy. • (v. i.) To associate or hold fellowship as brothers, or as men of like occupation or character; to have brotherly feelings.
Fra'ter·nize intransitive verb [ imperfect & past participle Fraternized ; present participle & verbal noun . Fraternizing .] [ Confer French fraterniser .] To associate or hold fellowship as brothers, or as men of like occupation ...
[v] - be on friendly terms with someone
fraternize, fraternization, fraternizer 1. To spend time with other people socially, especially people with whom you should not be friendly [those considered to be 'enemies']. 2. To enter into a sexual relationship with a person of a different rank against military regulations.
fraternise verb be on friendly terms with someone, as if with a brother, especially with an enemy