Ancient vampire rowing on lake (8)
I believe the answer is:
primeval
'ancient' is the definition.
(I've seen this before)
'vampire rowing on lake' is the wordplay.
I cannot really see how this works, but
an anagram of 'vampire' is 'primeva' which is present in the answer.
'lake' could be 'l' (geographical abbreviation) and 'l' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for primeval that I've seen before include "Ancient" , "Prehistoric" , "Instinctive" , "From the earliest times" , "Belonging to the Earth's beginnings" .)