Half-hearted attempt is regularly discouraged at the outset (5)
I believe the answer is:
tepid
'half-hearted' is the definition.
(I've seen this before)
'attempt is regularly discouraged at the outset' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'at the outset' indicates taking the first letters (the outset is the beginning).
The initial letter of 'discouraged' is 'd'.
'attempt'+'is'='attemptis'
The alternating letters of 'attemptis' are 'tepi'.
'tepi'+'d'='TEPID'
(Other definitions for tepid that I've seen before include "Moderately warm" , "Showing little interest or enthusiasm" , "Unenthusiastic - cool" , "Luke warm" , "lacking enthusiasm" .)