The most common and most likely answer to this crossword clue is the 7 letter word SOAPIER
I've seen this crossword clue in The Sunday Telegraph
S
O
A
P
I
E
R
Buddy explains!
The straight part
We know that "More foamy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case more foamy = soapier.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 SOAPIER mean?
SOAPIER adjective- Resembling soap.
- Resembling a soap opera.
- Full of soap.
- Covered in soap.
- Committing or involving flattery.