Very casual, drifting right of certain vessels (8)
I believe the answer is:
vascular
'very casual drifting right of certain vessels' is the definition.
I can't tell whether this defines the answer.
'very casual drifting right' is the wordplay.
'very' becomes 'v' (abbreviation).
'drifting' indicates an anagram.
'right' becomes 'r' (common abbreviation).
'casual' is an anagram of 'ascula'.
'v'+'ascula'+'r'='VASCULAR'
Can you help me to learn more?
(Other definitions for vascular that I've seen before include "Consisting of vessels for conveying blood" , "Relating to blood vessels" , "Relating to vessels that circulate fluids" , "Relating to blood-carrying vessels" , "Of vessels that circulate blood" .)