1. Boutade: A sudden outburst or outbreak

2. He returned to beg her pardon for his sudden outburst.

3. Coprolalia is a sudden outburst of inappropriate words, especially swear words

4. Their sudden outburst was obviously genuine; it couldn't have been contrived.

5. He had a sudden outburst against the whole tribe of actors.

6. He's always seemed very self-controlled, so I was amazed by his sudden outburst in the office.

7. He's always seemed very self-controlled(Sentence dictionary), so I was amazed by his sudden outburst in the office.

8. Amok: A syndrome first reported in the Malay people, usually male, consisting of a period of brooding followed by a sudden outburst of indiscriminate murderous frenzy, sometimes provoked by an insult, jealousy or sense of desperation