The most common and most likely answer to this crossword clue is the 4 letter word TITS
I've seen this crossword clue in The Guardian
T
I
T
S
Buddy explains!

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 TITS mean?
TITS noun- A mammary gland, teat.
- (chiefly in the plural) A woman's breast.
- An idiot; a fool.
- A police officer; a "tithead".
- A light blow or hit (now usually in the phrase tit for tat).
- A chickadee; a small passerine bird of the genus Parus or the family Paridae, common in the Northern Hemisphere.
- Any of various other small passerine birds.
- A small horse; a nag.
- A young girl, later especially a minx, hussy.
- A morsel; a bit.
- Very good; awesome; amazing.
- Used to express dismay or annoyance.
- Used to express excitement.