can of worms INFORMAL
a situation which causes a lot of problems for you when you start to deal with it:
Corruption is a serious problem, but nobody has yet been willing to open up that can of worms.

[TahlilGaran] Advanced Learner's Dictionary ▲

can of worms
[informal]
a situation which causes a lot of trouble for you when you start to deal with it.
Quite what we do with all the waste generated by this industry is another can of worms.

Once you start making concessions to individual members of staff, you really open up a can of worms.
(= cause a lot of trouble for yourself)

[TahlilGaran] English Idioms Dictionary ▲

can of worms
a complicated situation or problem
The lawsuit opened up a can of worms for the company.

[TahlilGaran] English Idioms Dictionary ▲

can of worms
n., slang, informal
1. A complex problem, or complicated situation.
Let's not get into big city politics
■ that's a different can of worms.
2. A very restless, jittery person.
Joe can't sit still for a minute
■ he is a can of worms.

[TahlilGaran] English Idioms Dictionary ▲