mediocre

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Of ordinary or undistinguished quality. synonym: average.

from The Century Dictionary.

• Of moderate degree or quality; middling; indifferent; ordinary.
• noun One of middling quality, talents, or merit.
• noun A monk between twenty-four and forty years of age, who was excused from the office of the chantry and from reading the epistle and gospel, but performed his duty in choir, cloister, and refectory.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Of a middle quality; of but a moderate or low degree of excellence; indifferent; ordinary.
• noun rare A mediocre person; a mediocrity.
• noun A young monk who was excused from performing a portion of a monk's duties.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Ordinary: not extraordinary; not special, exceptional, or great; of medium quality;

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective lacking exceptional quality or ability
• adjective moderate to inferior in quality
• adjective poor to middling in quality