Marginal (adjective)

1. Relating to or situated at the edge or margin of something.
2. Barely sufficient in amount or value.
3. Not of central importance.

Origin:

Mid 16th century (in the sense ‘written in the margin’): from medieval latin marginalis, from margo, margin- ‘edge’.

Examples:

1. The company's profits were only marginal last quarter.
2. The building was located in a marginal neighborhood.
3. The candidate won the election by a marginal majority.
4. He made only a marginal improvement on his last test score.
5. Her contributions to the project were considered marginal at best.