WordWeb Online

1. Changeable
   "freakish weather";
   - capricious
    
2. Characteristic of a freak
   "a freakish extra toe"
    
3. Conspicuously or grossly unconventional or unusual
   "a freakish combination of styles";
   - bizarre, eccentric, freaky [informal], flaky [informal], flakey [informal], gonzo [N. Amer, informal], off-the-wall [informal], outlandish, outré

See also: abnormal, unconventional, unnatural, unpredictable

Encyclopedia: Freakish