Rush job letters (4)
I believe the answer is:
asap
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rush job letters</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for asap that I've seen before include "Notation meaning with minimum delay" , "'As quickly as you can, initially (4)'" , "Notation or acronym meaning without avoidable delay" , "'At the earliest moment, initially (4)'" , "At the earliest opportunity (abbrev.)" .)