The most common and most likely answer to this crossword clue is the 4 plus 5 letter word COME AGAIN
I've seen this crossword clue in The Guardian
C
O
M
E
A
G
A
I
N
More clues leading to the result COME AGAIN
- Please return what?
- What in return?
- Pardon setter – a good anagram’s first in a bit
- Egomaniac sent out what?
- What did you say? Egomaniac needs a beating?
- I didn’t hear you say I’m welcome back
- What did you say about me living in Ohio once more?
- Pay another visit, eh?
- Sorry for what visitors might hear?
- Egomaniac should be upset and sorry
Buddy explains!

The straight part
We know that "I didn’t hear you/say I’m welcome back" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case i didn’t hear you/say i’m welcome back = come again.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.