The most common and most likely answer to this crossword clue is the 8 plus 5 letter word RUNCIBLE SPOON
R
U
N
C
I
B
L
E
S
P
O
O
N
Buddy explains!
The straight part
We know that "Newlyweds' odd utensil" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case newlyweds' odd utensil = runcible spoon.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.