The most common and most likely answer to this crossword clue is the 6 letter word LIBIDO
I've seen this crossword clue in Financial Times
L
I
B
I
D
O
More clues leading to the result LIBIDO
- Desire of party member to take union vow?
- Powerful urge beginning to lessen, I offer nothing
- Politician leading one party shows capacity for it
- Sexual drive of old politician associated with international party
- Desire shown by girl ultimately – then I offer love
- Desire freedom associated with marital consent?
- Urge party to give consent
- Drive and look around in the same place
- Desire for union to accept current offer, see
- Inspiring effort, painting recalled showing passion
Buddy explains!

The straight part
We know that "Desire" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case desire = libido.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 LIBIDO mean?
LIBIDO noun- The fraction of incident light or radiation reflected by a surface or body, commonly expressed as a percentage.
- The whitish inner portion of the rind of citrus fruits that is a source of pectin, commonly referred to as the pith.
- One of the four major stages of the magnum opus, involving purification of the prima materia.
- (common usage) Sexual urges or drives.
- Drives or mental energies related to or based on sexual instincts but not necessarily sexual in and of themselves.