'posi' as in positive; a word use among the hardcore/scene kids.
'luv' being a short form of love.
puting posi and luv together, is posiluv which means having a positive outlook on love and on life or having a positive like and vibe towards a certain type of music
friend 1 : you can tell she has very posiluv by the way shes with her boyfriend
friend 2 : she is always saying good things about relationships never bad
friend 1 : i wish i could be like that