Remove ludicrous tech ad (6)
I believe the answer is:
detach
'remove' is the definition.
(I've seen this in another clue)
'ludicrous tech ad' is the wordplay.
'ludicrous' is an anagram indicator (a ludicrous spelling).
'tech'+'ad'='techad'
'techad' is an anagram of 'DETACH'.
(Other definitions for detach that I've seen before include "Disengage (something) and remove it" , "Split off" , "free" , "Break off, come away" , "Remove from contact" .)