The most common and most likely answer to this crossword clue is the 5 letter word GROWL
I've seen this crossword clue in The Guardian
G
R
O
W
L
More clues leading to the result GROWL
- Turn left perhaps to warn of attack
- Threatening utterance to become pitiful in the end
- Increase length, prompting angry sound
- Get bigger medal at last, but react gruffly
- Snarl from Left after good argument
- Rise and large unfriendly dog may do this
- Angry sound of Greek bird
- What setter might do, having become larger at 50
- Greek member of parliament’s surly grumble
- Menacing sound from grey predator
Buddy explains!
The straight part
We know that "complain" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case complain = growl.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 GROWL mean?
GROWL noun- A deep, rumbling, threatening sound made in the throat by an animal.
- (by extension) The rumbling sound made by a person's stomach when hungry.
- (by extension) An aggressive grumbling.
- (by extension) A low-pitched rumbling sound produced with a wind instrument.
- To utter a deep guttural sound, as an angry animal; to give forth an angry, grumbling sound.
- Of a wind instrument: to produce a low-pitched rumbling sound.
- To send a user a message via the Growl software library.
- To express (something) by growling.
- To play a wind instrument in a way that produces a low-pitched rumbling sound.