1) Aberrant 2) Abnormal 3) An unusual hobby 4) An unusual response 5) Atypical 6) Bizarre 7) Colourful 8) Cruel partner 9) Curious 10) Different 11) Extraordinary 12) Falling short 13) Glamorous 14) Hardly commonplace 15) Infrequent 16) Innovative 17) Interesting 18) Irregular 19) Mysterious 20) Not commonly encountered 1) Aberrant 2) Abnormal 3) Antic 4) Arresting 5) Curious 6) Eccentric 7) Exceptional 8) Exotic 9) Extraordinary 10) Fanciful 11) Fantastic 12) Freakish 13) Freaky 14) Idiosyncratic 15) Inusitate 16) Irregular 17) New 18) Odd 19) Oddish 20) Particular 21) Peculiar 22) Quaint 23) Queer 24) Rare 25) Rum 
• (a.) Not usual; uncommon; rare; as, an unusual season; a person of unusual grace or erudition.
[adj] - not usual or common or ordinary 2. [adj] - not commonly encountered
adjective not commonly encountered; `two-career families are no longer unusual`
not usual, common, or ordinary; uncommon in amount or degree; exceptional: an unusual sound; an unusual hobby; an unusual response.