The most common and most likely answer to this crossword clue is the 8 letter word ATTAGIRL
I've seen this crossword clue in The Guardian
A
T
T
A
G
I
R
L
More clues leading to the result ATTAGIRL
Buddy explains!
The straight part
We know that "come on, young lady" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case come on, young lady = attagirl.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 ATTAGIRL mean?
ATTAGIRL interjection- Used to show encouragement or approval to a girl or woman. Female version of attaboy.