| Informal. a source of many unpredictable or unexpected problems: Buying a company we know nothing about would be opening up a whole new can of worms. |

can 2 (kān) n.
[Middle English canne, a water container, from Old English.] can'ner n. |
| can of worms n. pl. cans of worms Informal A source of unforeseen and troublesome complexity. |
can of worms
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can of worms
A complex unexpected problem or unsolvable dilemma, as in Tackling the budget cuts is sure to open a can of worms. This expression alludes to a container of bait used for fishing, which when opened reveals an inextricable tangle of worms. [1920s]