The most common and most likely answer to this crossword clue is the 5 letter word TORII
T
O
R
I
I
Buddy explains!
The straight part
We know that "temple gateway" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case temple gateway = torii.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.
What does TORII mean?
TORII noun- A traditional Japanese gate at Shinto shrines, symbolically marking the transition from the profane to the sacred.