The most common and most likely answer to this crossword clue is the 9 letter word DOWNRIGHT
I've seen this crossword clue in The Sunday Telegraph
D
O
W
N
R
I
G
H
T
More clues leading to the result DOWNRIGHT
- Depressed, having got put in order or rank
- Complete one sort of clue correctly
- Complete day throwing fits
- Absolutely depressed? Correct
- Utterly depressed? True
- Frank is out of order, don’t you agree?
- Not up left? Absolutely!
- Unqualified, losing claim
- Entitlement to drink is absolute!
- Totally blue, Conservative
Buddy explains!

The straight part
We know that "complete" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case complete = downright.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 DOWNRIGHT mean?
DOWNRIGHT adjective- Directed vertically; coming straight down.
- Directly to the point; plain
- Using plain direct language; accustomed to express opinions directly and bluntly; blunt.
- Complete; absolute
- Really; actually; quite
- Straight down; perpendicularly.
- Plainly, unambiguously; directly.
- Without delay; at once.