Thin porridge (5)
I believe the answer is:
gruel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">thin porridge</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 gruel that I've seen before include "cheap fare" , "Thin liquid food" , "Unappetising meal of boiled oatmeal" , "Thin food of boiled oatmeal" , "sloppy fare" .)