WordWeb Online

1. At or constituting a border or edge
   "the marginal strip of beach"
   - fringy
    
2. Of questionable or minimal quality
   "marginal writing ability"
   - borderline
    
3. Just barely adequate or within a lower limit
   "a marginal victory"
   - bare
    
4. Producing at a rate that barely covers production costs
   "marginal industries"
    
5. (statistics) having been marginalized

See also: margin, marginality, marginally, minimal, minimum, narrow, peripheral, unprofitable

Encyclopedia: Marginal