The most common and most likely answer to this crossword clue is the 7 letter word OBVERSE
I've seen this crossword clue in Independent
O
B
V
E
R
S
E
More clues leading to the result OBVERSE
- Heads round front of battle lines
- Mostly manage to retain British monarch's head here
- Heads up to see the other side of the coin
- Front of brochure primarily poet’s work
- Poetry by leaders in benefits office turned heads
- Heads round Britain, gaining victory over Irish
- Change ‘observe’ into the opposite
- Penny’s face maybe when old boy introduces poetry
- Head presents alumnus with some poetry
- Old British rhyme written on this side of coin?
Buddy explains!

The straight part
We know that "The opposite" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case the opposite = obverse.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 OBVERSE mean?
OBVERSE noun- The heads side of a coin, or the side of a medal or badge that has the principal design.
- A proposition obtained by obversion, e.g. All men are mortal => No man is immortal.
- Turned or facing toward the observer.
- Corresponding; complementary.
- Having the base, or end next to the attachment, narrower than the top.