Huge beast stood out in island (8)
I believe the answer is:
'huge beast' is the definition.
'mastodon' can be an answer for 'beast' (mastodon is a kind of beast). I'm not sure about the 'huge' bit.
'stood out in island' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'in' indicates putting letters inside.
'island' becomes 'man' (the Isle of Man is an example).
'stood' with letters rearranged gives 'stodo'.
'stodo' inserted within 'man' is 'MASTODON'.
Can you help me to learn more?
(Other definitions for mastodon that I've seen before include "Extinct beast" , "Man stood like extinct sort of elephant" , "Extinct mammal like an elephant" , "Old mammal" , "Extinct elephant-like mammal" .)