Souvenir from castle’s main tower accompanied by drink (8)
I believe the answer is:
keepsake
'souvenir from castle's main' is the definition.
'keepsake' can be an answer for 'souvenir' (synonyms). I'm unsure of the 'from castle's main' bit.
'tower accompanied by drink' is the wordplay.
'tower' becomes 'keep' (I've seen this before).
'accompanied by' says to put letters next to each other.
'drink' becomes 'sake' (sake is a kind of drink).
'keep'+'sake'='KEEPSAKE'
Can you help me to learn more?
(Other definitions for keepsake that I've seen before include "one recalls" , "Souvenir, memento" , "token" , "Remembrance" , "to remember one by" .)