en·fant ter·ri·ble 
(äɴ-fäɴ′ tĕ-rēblə)
(äɴ-fäɴ′ tĕ-rēblə)n. pl. en·fants ter·ri·bles (äɴ-fäɴ′ tĕ-rēblə)
One whose startlingly unconventional behavior, work, or thought embarrasses or disturbs others: The radical painter was the enfant terrible of the art establishment.
[French : enfant, child + terrible, frightful.]