Dad took off, or mum left? Hard to explain (10)
I believe the answer is:
paranormal
'hard to explain' is the definition.
(not explained by science)
'dad took off or mum left?' is the wordplay.
'dad' becomes 'pa' (both can mean one's father).
'took off' becomes 'ran' (I've seen this in another clue).
'mum left?' becomes 'mal' (I can't justify this - if you can you should believe this answer much more).
'pa'+'ran'+'or'+'mal'='PARANORMAL'
Can you help me to learn more?
(Other definitions for paranormal that I've seen before include "mystic" , "on a higher plane?" , "Scientifically inexplicable" , "Beyond scientific understanding" , "Supernatural" .)