Large tentacled creature raised behind pub is extraordinary (10)
I believe the answer is:
phenomenal
'extraordinary' is the definition.
(similar in meaning)
'large tentacled creature raised behind pub' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'tentacled creature' becomes 'anemone' (I can't explain this - if you can you should give a lot more credence to this answer).
'raised' says the letters should be written backwards (going up in a down clue).
'behind' is a charade indicator (letters next to each other).
'pub' becomes 'ph' (public house).
'l'+'anemone'='lanemone'
'lanemone' in reverse letter order is 'enomenal'.
'enomenal' after 'ph' is 'PHENOMENAL'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for phenomenal that I've seen before include "Remarkable" , "Unusual" , "Extraordinary - help one man (anag)" , "Incredible" , "Mind-blowing" .)