The most common and most likely answer to this crossword clue is the 5 letter word DOBBY
D
O
B
B
Y
Buddy explains!
The straight part
We know that "Silly old fellow" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case silly old fellow = dobby.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 DOBBY mean?
DOBBY noun- A device in some looms that allows the weaving of small geometric patterns.
- The patterns so woven, or the fabric containing the patterns.
- An evil or mischievous fairy or ghost sometimes said to haunt a building or household.
- A dotard.