marginal in WordNet English dictionary

1. just barely adequate or within a lower limit
   "a bare majority"; "a marginal victory"
   bare  marginal 
   
2. of questionable or minimal quality
   "borderline grades"; "marginal writing ability"
   borderline  marginal 
   
3. at or constituting a border or edge
   "the marginal strip of beach"
   fringy  marginal 
   
4. producing at a rate that barely covers production costs
   "marginal industries"
   marginal