The most common and most likely answer to this crossword clue is the 6 letter word STRUNG
S
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R
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Buddy explains!
The straight part
We know that "tied up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tied up = strung.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 STRUNG mean?
STRUNG verb- To put (items) on a string.
- To put strings on (something).
- To form into a string or strings, as a substance which is stretched, or people who are moving along, etc.
- To drive the ball against the end of the table and back, in order to determine which player is to open the game.
- To deliberately state that a certain bird is present when it is not; to knowingly mislead other birders about the occurrence of a bird, especially a rarity; to misidentify a common bird as a rare species.