Slipshod, slapdash (8)
I believe the answer is:
careless
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">slipshod</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">slapdash</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for careless that I've seen before include "'Thoughtless, inattentive (8)'" , "Inattentive and negligent" , "Cavalier" , "Sloppy" , "impetuous" .)