The most common and most likely answer to this crossword clue is the 12 letter word COMPARATIVES
I've seen this crossword clue in The Guardian
C
O
M
P
A
R
A
T
I
V
E
S
Buddy explains!
The straight part
We know that "luckier, happier better, perhaps" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case luckier, happier better, perhaps = comparatives.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 COMPARATIVES mean?
COMPARATIVES noun- (grammar) A construction showing a relative quality, in English usually formed by adding more or appending -er. For example, the comparative of green is greener; of evil, more evil.
- (grammar) A word in the comparative form.
- (chiefly in the plural) Data used to make a comparison.
- An equal; a rival; a compeer.
- One who makes comparisons; one who affects wit.