The most common and most likely answer to this crossword clue is the 7 letter word SAFARIS
I've seen this crossword clue in The Guardian
S
A
F
A
R
I
S
Buddy explains!

The straight part
We know that "expeditions/t" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case expeditions/t = safaris.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 SAFARIS mean?
SAFARIS noun- A trip into any undeveloped area to see, photograph or hunt wild animals in their own environment.
- A caravan going on a safari.
- To take part in a safari.