Sentence:  In a second, we all three fell back on the roof of the coach, hiding our faces with our hands, and committing that gross act of <WSD>"ostrichism</WSD>" of fancying, because we could not see that we escaped observation. 
Meaning of the word marked with <WSD> tags:  The act of hiding, often unsuccessfully, by ducking one's head out of view. (from mid 19th c.)