E.g. Picaroon in terrible dump? Yes and no (9)
I believe the answer is:
pseudonym
'e g picaroon' is the definition.
I can't tell whether this definition defines the answer.
'terrible dump? yes and no' is the wordplay.
'terrible' is an anagram indicator.
'and' means one lot of letters go next to another.
'dump'+'yes'='dumpyes'
'dumpyes' after 'no' is 'nodumpyes'.
'nodumpyes' anagrammed gives 'PSEUDONYM'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for pseudonym that I've seen before include "Lewis Carroll, for one" , "Pen-name" , "another title" , "in the style of George Eliot?" , "Lewis Carroll, perhaps?" .)