The most common and most likely answer to this crossword clue is the 4 letter word TASS
I've seen this crossword clue in Financial Times
T
A
S
S
Buddy explains!

The straight part
We know that "Goblet" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case goblet = tass.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 TASS mean?
TASS noun- A heap, pile.
- A cup or cupful.
- A piece of armor for the thighs, forming an appendage to the ancient corselet. Usually the tasse was a plate of iron swinging from the cuirass, but the skirts of sliding splints were also called by this name.
- An Oriental silk fabric, with gold or silver thread.