I've gone after ghastly shade that's tacky (8)
I believe the answer is:
adhesive
'tacky' is the definition.
(I've seen this before)
'i've gone after ghastly shade' is the wordplay.
'gone after' says to put letters next to each other.
'ghastly' indicates an anagram (I've seen this in other clues).
'shade' anagrammed gives 'adhes'.
'ive' after 'adhes' is 'ADHESIVE'.
'that's' acts as a link.
(Other definitions for adhesive that I've seen before include "Binding" , "Stuff that sticks" , "very clingy" , "Glue, gum" , "What a sticker" .)