heckler:
(also called ‘badgerer‘; plural: ‘hecklers‘)
a person who interrupts (disturbs by getting between) a speaker or a speech with shouts or confusing or unfriendly remarks, especially at a political meeting,

(a cartoon of a heckler (L, white) from the audience heckling/interrupting a speaker on the dais (R, blue)
The Chairman’s speech last night was a debacle because of a heckler who kept interrupting and refused to leave the meeting hall until the Chairman answered his questions about the financial situation of the committee, which was very embarrassing for the entire committee.
Heckling, the act of interrupting a speaker or a programme, has become a regular feature at political meetings, and every political party has some intrepid hecklers whose unofficial job is to heckle opponents.
It’s disgusting to know that some celebrities hire ‘professional hecklers’ either to give them a chance to show off to get free publicity or to interrupt and ruin well-organised programmes of their rivals!
It has a become a standard procedure for all the state leaders to take a few classes on how to handle hecklers without losing their temper in public.
