Terrifying beast men sort out (7)
I believe the answer is:
monster
'terrifying beast' is the definition.
'monster' can be an answer for 'beast' (I have seen 'Imaginary beast' mean 'monster' so perhaps 'beast' could also mean 'monster'). I am not certain of the 'terrifying' bit.
'men sort out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'men'+'sort'='mensort'
'mensort' is an anagram of 'MONSTER'.
Can you help me to learn more?
(Other definitions for monster that I've seen before include "Inhuman person" , "Frightening creature of folklore" , "Ogre, demon" , "Large, ugly and frightening imaginary creature" , "Fabled giant animal" .)