The most common and most likely answer to this crossword clue is the 5 letter word ORACY
O
R
A
C
Y
Buddy explains!
The straight part
We know that "Ability to express oneself" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ability to express oneself = oracy.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 ORACY mean?
ORACY noun- The ability to speak, and to understand spoken language
- A measure of this ability