Playwright, Shaw, not half confusing reading, mostly (8)
I believe the answer is:
sheridan
'playwright' is the definition.
(I've seen this before)
'shaw not half confusing reading mostly' is the wordplay.
'not half' suggests halving the letters.
'confusing' indicates an anagram.
'mostly' means to remove the last letter.
'shaw' with half the letters taken is 'sh'.
'reading' with its last letter removed is 'readin'.
'readin' anagrammed gives 'eridan'.
'sh'+'eridan'='SHERIDAN'
(Other definitions for sheridan that I've seen before include "Richard Brinsley ........, Anglo-Irish author of ` `The School for Scandal' '" , "Irish playwright and politician, d. 1816" , "- Le Fanu, Ir. novelist" , "general, esteemed by Americans" , "Creator of Mrs Malaprop in The Rivals" .)