Request a response from sometimes brash Vice President (4)
I believe the answer is:
rsvp
'request a response' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'sometimes brash vice president' is the wordplay.
'sometimes' indicates alternate letters (some of the letters are taken at regular intervals).
'vice president' becomes 'V.P.' (synonyms).
The alternating letters of 'brash' are 'rs'.
'rs'+'vp'='RSVP'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for rsvp that I've seen before include "Answer! (Fr.)" , "Please reply to the French, in short" , "Notation meaning answer the invitation" , "Please reply (abbrev.)" , "Can you come to the party?" .)