One upright, holy man with tablets (7)
I believe the answer is:
standee
'one upright' is the definition.
The definition suggests a singular noun which matches the answer.
'holy man with tablets' is the wordplay.
'holy man' becomes 'st' (abbreviation for saint).
'with' becomes 'and'.
'tablets' becomes 'EE' (more than one Ecstasy pill).
'st'+'and'+'ee'='STANDEE'
Can you help me to learn more?
(Other definitions for standee that I've seen before include "Rush hour traveller, perhaps" , "One without seat in bus" , "who doesn't have a seat?" , "I can't settle comfortably in America" .)