The most common and most likely answer to this crossword clue is the 3 plus 8 letter word BOG STANDARD
I've seen this crossword clue in The Sunday Telegraph
B
O
G
S
T
A
N
D
A
R
D
More clues leading to the result BOG STANDARD
Buddy explains!
The straight part
We know that "Unspectacular" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unspectacular = bog standard.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 BOG STANDARD mean?
BOG STANDARD adjective- Utterly basic, ordinary, or standard; unremarkable, unexceptional, etc.