Acquired relatives (2-4)
I believe the answer is:
in-laws
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">acquired relatives</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 in-laws that I've seen before include "Relatives by marriage 2-4)" , "Christmas is when you might bid them welcome" , "Spouse's relations" , "A person's relatives by marriage" , "Family of your spouse" .)