The most common and most likely answer to this crossword clue is the 10 letter word ANTECEDENT
I've seen this crossword clue in The Times
A
N
T
E
C
E
D
E
N
T
Buddy explains!
The straight part
We know that "Former" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case former = antecedent.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 ANTECEDENT mean?
ANTECEDENT noun- Any thing that precedes another thing, especially the cause of the second thing.
- An ancestor.
- (grammar) A word, phrase or clause referred to by a pronoun.
- The conditional part of a hypothetical proposition, i.e. p \rightarrow q, where p is the antecedent, and q is the consequent.
- The first of two subsets of a sequent, consisting of all the sequent's formulae which are valuated as true.
- The first term of a ratio, i.e. the term a in the ratio a:b, the other being the consequent.
- (chiefly in the plural) Previous principles, conduct, history, etc.
- Earlier, either in time or in order.
- Presumptive.