What is the meaning to 'bury your head in the sand'?

Answer 1

The origin of the phrase is the (mistaken) belief that the ostrich buries its head when in danger .

Today the expression means to ignore unwanted news or events in the hope that they will go away.

Answer 2

It means you're ignoring an unpleasant fact or situation, in the hopes that it'll change.

It comes from the idea that ostriches supposedly bury their heads to deter predators, which doesn't sound like a very good survival strategy.
Directly from the first attested European quote about the ostrich's feeding habit in sand moss or loose soil; "Alike (the) Austridge, who hiding her little head, supposeth her great body obscured" [1623] ...the meaning implying the ostrich is meant to be 'hiding' while the rest of its body remains visible, likened to a child 'hiding' its eyes and becoming 'invisible' thereby. ________________________________________________________________ to avoid hearing or seeing anything happening around you
Head in the sand means hiding from the troubles that face you. Not standing up to danger. It refers to the myth that an ostrich when confronted will hide their heads in the sand even though it is not true.

Answer 3

It means to ignore something, even when that something could be dangerous to the person in question or to those on whom he/she bears responsibility.

The imagery comes from the (erroneous) belief that ostriches bury their heads in the sand. The idea is that, with one's head under the ground not able to see or hear outside, they aren't aware of what's going on: usually at a time when they SHOULD be aware.

The phrase can be used more forcefully to imply that this ignorance is intentional and that the object of the idiom is making a very poor response to a crisis.