The most common and most likely answer to this crossword clue is the 6 letter word HYBRID
I've seen this crossword clue in The Guardian
H
Y
B
R
I
D
More clues leading to the result HYBRID
- Cross in past hour, upset, then relieved
- Cross new wife briefly chasing gutless hubby
- Cross and upset by horse getting shot
- Driven back by hard shot, becoming cross
- Cross crunchy bridge with bits falling off the sides
- Shy bride holding cross
- Using combined power to undress shy bride
- Cross Henry I appearing in Byrd composition
- Cross borne by worthy bridegroom
- Shy bride clutching cross
Buddy explains!

The straight part
We know that "Cross" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cross = hybrid.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 HYBRID mean?
HYBRID noun- Offspring resulting from cross-breeding different entities, e.g. two different species or two purebred parent strains.
- Something of mixed origin or composition; often, a tool or technology that combines the benefits of formerly separate tools or technologies.
- Consisting of diverse 'hybridized' components.