Somehow derive stimuli with one appearance of reality (14)
I believe the answer is:
verisimilitude
'appearance of reality' is the definition.
'verisimilitude' can be an answer for 'reality' (I have seen 'apparent reality' mean 'verisimilitude' so perhaps 'reality' could also mean 'verisimilitude'). I am unsure of the 'appearance of' bit.
'somehow derive stimuli with one' is the wordplay.
'somehow' indicates anagramming the letters.
'with' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'derive'+'stimuli'='derivestimuli'
'derivestimuli' is an anagram of 'verisimlitude'.
'verisimlitude' enclosing 'i' is 'VERISIMILITUDE'.
Can you help me to learn more?
(Other definitions for verisimilitude that I've seen before include "Appearance of being true" , "semblance of truth" , "apparent reality" .)