The most common and most likely answer to this crossword clue is the 5 letter word STAFF
I've seen this crossword clue in Independent
S
T
A
F
F
More clues leading to the result STAFF
Buddy explains!

The straight part
We know that "support" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case support = staff.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 STAFF mean?
STAFF noun- (plural staffs or staves) A long, straight, thick wooden rod or stick, especially one used to assist in walking.
- (plural staves) A series of horizontal lines on which musical notes are written; a stave.
- (plural staff or staffs) The employees of a business.
- A mixture of plaster and fibre used as a temporary exterior wall covering.W
- A pole, stick, or wand borne as an ensign of authority; a badge of office.
- A pole upon which a flag is supported and displayed.
- The rung of a ladder.
- A series of verses so disposed that, when it is concluded, the same order begins again; a stanza; a stave.
- An arbor, as of a wheel or a pinion of a watch.
- The grooved director for the gorget, or knife, used in cutting for stone in the bladder.
- An establishment of officers in various departments attached to an army, to a section of an army, or to the commander of an army. The general's staff consists of those officers about his person who are employed in carrying his commands into execution.
- To supply (a business, volunteer organization, etc.) with employees or staff members.