The term 'hard-to-explain something' can be summarized by the crossword solution 'AURA'. An AURA is a type of energy field that surrounds living things, such as people and animals. It is believed to be composed of spiritual or emotional energy, and is often associated with a feeling of peace or calmness. Auras are difficult to explain because they cannot be seen or touched, and are only perceived through intuition or other forms of extrasensory perception.