what is a dangling modifier?

Answer 1

A dangling modifier is a word of phrase meant to modify another word or phrase, but due to phrasing, it's appearing to modify an unintended word or phrase (or something completely outside the sentance). It generally makes a sentance harder to read and parse, and may lead to confusion.

Example from the 1918 Elements of Style:
"Being in a dilapidated condition, I was able to buy the house very cheap." - on first glance, you'd think you were saying that "I" was in a dilapidated condition, not "the house".