The most common and most likely answer to this crossword clue is the 7 letter word TESTIFY
I've seen this crossword clue in The Daily Telegraph
T
E
S
T
I
F
Y
More clues leading to the result TESTIFY
- Fully cleared after sounding angry, swear
- Assert cricket match dodgy? F-off!
- . Appear in court, say, if brought in quarrelsome
- Some protest if you bear witness to the Lord
- Bear witness to being irritable about condition
- Cross bridges if to give evidence
- Irritable if brought in to give evidence
- Liable to be angry about providing witness
- Witness impatient to see one fellow incarcerated
- Irritable if made to go inside to give evidence
Buddy explains!

The straight part
We know that "to give evidence" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case to give evidence = testify.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 TESTIFY mean?
TESTIFY verb- To make a declaration, or give evidence, under oath.
- To make a statement based on personal knowledge or faith.