The most common and most likely answer to this crossword clue is the 7 letter word TEEMING
I've seen this crossword clue in Independent
T
E
E
M
I
N
G
More clues leading to the result TEEMING
- Pouring drink, reportedly, requiring Chinese porcelain
- Packed with group of players speaking in German
- Appearing topless after casual shirt becomes full of creatures?
- Where drivers are stuck on motorway – no good seething
- Coming down hard, leaderless regiment gets beaten
- Pouring, though appearing to have time for start
- Golfer might be doing this, grabbing head of mashie and chucking it down
- Meeting turns out to be full
- Packed for yoking, by the sound of it
- Lousy casual clothing dynasty
Buddy explains!

The straight part
We know that "Packed with" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case packed with = teeming.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 TEEMING mean?
TEEMING verb- To be stocked to overflowing.
- To be prolific; to abound; to be rife.
- To bring forth young, as an animal; to produce fruit, as a plant; to bear; to be pregnant; to conceive; to multiply.
- To empty.
- To pour (especially with rain)
- To pour, as steel, from a melting pot; to fill, as a mould, with molten metal.
- To think fit.
- Abundantly filled with especially living things.
- Referring to large quantities of rain.