partisan - Dictionary definition and meaning for word partisan
parti(think of a political party)+san(son)...so a father who is favouring his son's political party, instead of a good party.
A partisan says, 'my party is my SON, my daughter, my mom & my dad'
PARTison -> taking a PART or side
Partisan almost sounds like "party-fan".. Someone who strongly supports partying it up :)