WordWeb Online

1. (of quantities) imprecise but fairly close to correct
   "holds 3 gallons, more or less";
   - approximately, about, close to, just about, some, roughly, around, or so, loosely
    
2. To a small degree or extent
   "the children argued because one slice of cake was more or less larger than the other";
   - slightly, somewhat, fractionally, marginally, tad [informal], a bit

Encyclopedia: More or less