temperamental


temperamental (http://definr.com/temperamental)

     adj 1: relating to or caused by temperament; "temperamental
            indifference to neatness"; "temperamental
            peculiarities"
     2: subject to sharply varying moods; "a temperamental opera
        singer" [syn: moody]
     3: likely to perform unpredictably; "erratic winds are the bane
        of a sailor"; "a temperamental motor; sometimes it would
        start and sometimes it wouldn't"; "that beautiful but
        temperamental instrument the flute"- Osbert Lancaster
        [syn: erratic]