Expert immersed in tea-blending (4)
I believe the answer is:
able
'expert' is the definition.
(I've seen this in other clues)
'immersed in tea-blending' is the wordplay.
'immersed in' indicates a hidden word.
'ABLE' can be found hidden inside 'tea blending'.
(Other definitions for able that I've seen before include "Capable seaman" , "Competent as seaman may be" , "Proficient; skilful" , "As capable as a mariner" , "Bale out, being competent" .)