A modifier literally means something or someone that modifies or adjusts something. But when it comes to English language and more specifically English grammar, a modifier is a word or phrase that describes or tells something more about one special word that it is used for.
Baby, astonished, opened her eyes wide.
Placement of a modifier
The placement of a modifier in a sentence is of vital importance and whenever you are using any modifier be sure to put it near the object that it is used to describe. It can be placed before or after the object.
Being late for dinner, Sara apologized to her mom.
Sometimes, in writing the writer is unable to put the modifier and the doer well together which leaves the reader confused. Some inexperienced writers put the modifier in the sentence but forget to place the person or thing that the modifier is intended to describe, thus leaving the modifier dangling there in a sentence without a purpose.
Now take this example and see for yourself. The modifier in this sentence is thirsty. Can you find a suitable subject or object in the sentence which thirsty describes? No. Because there isn’t one. The writer failed to use the modifier correctly in the sense that he used the modifier but did not mention the subject. Thus thirsty is a dangling modifier.