The most common and most likely answer to this crossword clue is the 3 letter word PST
P
S
T
More clues leading to the result PST
Buddy explains!
The straight part
We know that "Introduction to private tip-o?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case introduction to private tip-o? = pst.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 PST mean?
PST interjection- Implies that the speaker is sending secret or whispered information to another person.