1. highly prudish and high-strung person (usu. white female) from upper-middle class suburbs who can't stay out and have a good time because she has to go home and 'pack' or 'knit' or other such assinine 'obligations'
2. also, someone (usu. white female) who cannot refrain from delivering minute and unjustified critism, i.e. nit-pick
Guy: Why're you going home so early... it's Friday night!
Knitpacker: Yeah... but I have to go home and organize my linen closet.