Retaliation - keep after it, blocking pretentious stuff (3,3,3)
I believe the answer is:
tit for tat
'retaliation' is the definition.
(I've seen this in another clue)
'keep after it blocking pretentious stuff' is the wordplay.
I cannot really understand how this works, but
'keep' could be 'fort' (I've seen this in other clues) and 'fort' is present in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
'stuff' could be 'tat' (I have seen 'Shoddy stuff' mean 'tat' so perhaps 'stuff' could also mean 'tat') and 'tat' is found in the answer.
A single letter 'i' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tit for tat that I've seen before include "An eye for an eye" , "revenge" , "In annoyance, return" , "Retaliation in kind" , "Retaliation called for" .)