put the mockers on
put the mockers on (something)
To disrupt, foil, or cause problems to someone's plan, activity, or project. Primarily heard in UK. The caterer cancelled on me at the last minute, which really puts the mockers on this party! It will really put the mockers on our project if the board decides not to increase our funding. You would think the rise of cheap electric cars would put the mockers on Big Oil's profits, but they actually seem to be embracing the change.
put the mockers on1 put an end to; thwart. 2 bring bad luck to.
This expression originated as early 20th-century British slang. An Australian variant is put the mocks on.
1 1966 Lionel Davidson A Long Way to Shiloh Shimshon and the judo both seemed to have put the mockers on this particular idyll. We left soon after.
2 1970 Joyce Porter Dover Strikes Again This investigation had got the mockers on it from the start.