The most common and most likely answer to this crossword clue is the 4 letter word ONTO
O
N
T
O
Buddy explains!

The straight part
We know that "Aware of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case aware of = onto.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 ONTO mean?
ONTO adjective- (of a function) Assuming each of the values in its codomain; having its range equal to its codomain.
- Upon; on top of.
- Aware of.
- Being an onto function with a codomain of (see below).