The most common and most likely answer to this crossword clue is the 4 plus 5 letter word SOFT TOUCH
I've seen this crossword clue in The Daily Telegraph
S
O
F
T
T
O
U
C
H
More clues leading to the result SOFT TOUCH
Buddy explains!
The straight part
We know that "One can be easily fooled" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one can be easily fooled = soft touch.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.