The most common and most likely answer to this crossword clue is the 7 letter word DADAIST
I've seen this crossword clue in The Times
D
A
D
A
I
S
T
More clues leading to the result DADAIST
- What Man Ray was, having a platform in outskirts of Detroit
- Follower of artistic style, pop, as it changed
- Child's father is ahead of time as unconventional painter
- Max Ernst possibly Pop Artist? Not right
- Dutch woman is Utrecht’s ultimate 20th-century artist
- Artist’s father a good person, I admitted
- Style said to be warped by traditionalists for a start, anti-bourgeois
- Aesthetically unconventional daughter’s on a platform on time
Buddy explains!

The straight part
We know that "What Man Ray was" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what man ray was = dadaist.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.