The most common and most likely answer to this crossword clue is the 6 letter word TITLES
I've seen this crossword clue in The Daily Telegraph
T
I
T
L
E
S
More clues leading to the result TITLES
- Ranks Scrabble letters required in ‘tango’? The opposite
- Championships appearing in TV credits
- Associations taking time to get letterhead for offices
- IsDot not the source source of these Socialists' names
- One’s not into fancy elitist names
- E.g., Count Basie and Duke Ellington playing pieces, keeping in time
Buddy explains!

The straight part
We know that "Ranks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ranks = titles.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 TITLES mean?
TITLES noun- A prefix (honorific) or suffix (post-nominal) added to a person's name to signify either veneration, official position or a professional or academic qualification. See also
- Legal right to ownership of a property; a deed or other certificate proving this.
- In canon law, that by which a beneficiary holds a benefice.
- A church to which a priest was ordained, and where he was to reside.
- The name of a book, film, musical piece, painting, or other work of art.
- A publication.
- A section or division of a subject, as of a law or a book.
- (chiefly in the plural) A written title, credit, or caption shown with a film, video, or performance.
- The panel for the name, between the bands of the back of a book.
- The subject of a writing; a short phrase that summarizes the entire topic.
- A division of an act of law
- The recognition given to the winner of a championship in sports.