The most common and most likely answer to this crossword clue is the 6 letter word LATTER
I've seen this crossword clue in The Daily Telegraph
L
A
T
T
E
R
More clues leading to the result LATTER
- Bow milliner, perhaps, put on line second
- Second option is coffee with last of sugar
- Near the end some regret talking back
- The second drink ending in disaster
- Second coffee before last of beer
- Racket’s not caught the second one
- Mormon treats Lady Gaga with first-rate bible
- Second dish has penny off
- The second of two races in genuine reversal
- Modern type of coffee, right?
Buddy explains!

The straight part
We know that "The second of two" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case the second of two = latter.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 LATTER mean?
LATTER adjective- Relating to or being the second of two items.
- Near (or nearer) to the end.
- In the past, but close (or closer) to the present time.