Underage person grasping cross bullish monster (8)
I believe the answer is:
minotaur
'bullish monster' is the definition.
'Minotaur' can be an answer for 'monster' (Minotaur is an example). I'm not certain of the 'bullish' bit.
'underage person grasping cross' is the wordplay.
'underage person' becomes 'minor' (I've seen this in another clue).
'grasping' means one lot of letters goes inside another.
'cross' becomes 'tau' (tau cross is a kind of cross).
'minor' enclosing 'tau' is 'MINOTAUR'.
Can you help me to learn more?
(Other definitions for minotaur that I've seen before include "Am in rout of a fabulous monster" , "Creature, half-man and half-bull, slain by Theseus in the Cretan maze" , "Monster, half bull and half man, slain by Theseus in Cretan labyrinth" , "Beast of legend" , "Mythical man-bull" .)