The most common and most likely answer to this crossword clue is the 5 letter word MIMED
I've seen this crossword clue in The Times
M
I
M
E
D
Buddy explains!

The straight part
We know that "Silently indicated" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case silently indicated = mimed.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 MIMED mean?
MIMED verb- To mimic.
- To act without words.
- To represent an action or object through gesture, without the use of sound.