The most common and most likely answer to this crossword clue is the 7 letter word DETENTE
I've seen this crossword clue in The Daily Telegraph
D
E
T
E
N
T
E
More clues leading to the result DETENTE
- Partially divide ten territories, lessening hostility
- Period of relaxation having taking a knock largely with alien invasion
- A mutual easing of tensions inside ten terraced houses
- Relaxing Muscadet combined with entertaining shows
- Climate warmed with this shelter plunged into river?
- Relief when river is kept outside shelter
- One pitched in river for easing of tension
- A warming-up made tent expand in one section
- Attendee not originally disturbed in accommodation
- Bivouac, protected by river, offers an easing of tension
Buddy explains!

The straight part
We know that "an easing of tension" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case an easing of tension = detente.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 DETENTE mean?
DETENTE noun- A relaxing of tension, especially between countries.