The most common and most likely answer to this crossword clue is the 8 letter word APPARENT
I've seen this crossword clue in Financial Times
A
P
P
A
R
E
N
T
More clues leading to the result APPARENT
- A quiet member of the family, that's evident
- Progenitors going up and down plain
- Clear a mum or dad to adopt Penny
- Seeming appropriate to maintain standard in French
- Seeming to turn old man against old man?
- Patent obtained by a patient’s first carer?
- Dad’s up and down? That’s obvious
- Dad is back at his job, that’s clear
- It’s plain Dad is going back and forth with payment
- When father came up by himself, the rift was unmistakable
Buddy explains!

The straight part
We know that "It’s plain" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s plain = apparent.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 APPARENT mean?
APPARENT adjective- Capable of being seen, or easily seen; open to view; visible to the eye, eyely; within sight or view.
- Clear or manifest to the understanding; plain; evident; obvious; known; palpable; indubitable.
- Appearing to the eye or mind (distinguished from, but not necessarily opposed to, true or real); seeming.