The most common and most likely answer to this crossword clue is the 2 plus 6 letter word IN TANDEM
I've seen this crossword clue in The Guardian
I
N
T
A
N
D
E
M
More clues leading to the result IN TANDEM
- Together at home, having met up — and inside!
- Tim and Ned with day gone working as a partnership?
- Manned it at sea, together
- At home, cycle together
- To get together, cycle home first
- Everyman is grabbing ten and dancing together
- At the same time halving quaint island item
- Together in print and embossed
- Saint and emissary keeping close together
- Dignity, regularly with writer, retired together
Buddy explains!
The straight part
We know that "With 11 21/With 11 21" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case with 11 21/with 11 21 = in tandem.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.