Become liable to (5)
I believe the answer is:
incur
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">become liable to</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for incur that I've seen before include "Sustain" , "Bring something unpleasant on oneself (5)" , "Become responsible for" , "Enter into" , "Fall liable to" .)