The most common and most likely answer to this crossword clue is the 2 plus 3 letter word BY FAR
I've seen this crossword clue in The Times
B
Y
F
A
R
More clues leading to the result BY FAR
- Farewell note heard easily
- Discontented fairy keels over in pub, leaving the rest standing
- Very much cake, case of forty or fifty eaten up
- Very much why fellow boozer drinks
- Easily concealed in Selby farmhouse
- Reportedly purchase most of the food easily
- Burns, climbing around southern tip of sunny France, easily
- British and Yankee airmen travelling skywards easily
Buddy explains!

The straight part
We know that "easily" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case easily = by far.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.