A mate, companion, or associate.
(RQ:Tennyson In Memoriam)
A companion in battle; fellow soldier.
(quote-book)
A fellow socialist, communist or other similarly politically aligned person.
(ux)
(non-gloss definition)
To associate with in a friendly way.
{{quote-text|en|year=1916|author=Mark Twain|title=The Mysterious Stranger