The most common and most likely answer to this crossword clue is the 4 letter word ODER
I've seen this crossword clue in The Times
O
D
E
R
More clues leading to the result ODER
- River’s current, between banks
- IT expert losing top in German river
- German banker rejected note after note
- River current taking out both banks?
- Poem written on river, one flowing into Baltic
- Duck beginning to dabble with hesitation in river
- European river, stretch of Loire doubling back
- German banker returning to have another go
- Flower that’s yellow, outside Germany or in it
- Lines start to reflect river
Buddy explains!
The straight part
We know that "one flowing into Baltic" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one flowing into baltic = oder.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.