The most common and most likely answer to this crossword clue is the 4 letter word LEFT
I've seen this crossword clue in The Times
L
E
F
T
More clues leading to the result LEFT
- Socially progressive article in French paper
- Abandoned political grouping
- Allowed to drink fine port
- Departed from port
- Was substituted? Strange!
- Like continental estate, perhaps, bequeathed to present doctor I have
- Socialist's position on team?
- Resigned, he had to box with southpaw
- Socialists abandoned side
- Sinister sportspeople?
Buddy explains!

The straight part
We know that "Socially progressive" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case socially progressive = left.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 LEFT mean?
LEFT noun- The left side or direction.
- The ensemble of left-wing political parties. Those holding left-wing views as a group.
- The left hand or fist.
- A punch delivered with the left fist.
- A wave breaking from left to right (viewed from the shore).
- The opposite of right; toward the west when one is facing north.
- Pertaining to the political left.
- On the left side.
- Towards the left side.
- Towards the political left.
- To have a consequence or remnant.
- To depart; to separate from.
- To transfer something.
- To remain (behind); to stay.
- To stop, desist from; to "leave off" (+ noun / gerund).
- To give leave to; allow; permit; let; grant.
- To have a consequence or remnant.
- To depart; to separate from.
- To transfer something.
- To remain (behind); to stay.
- To stop, desist from; to "leave off" (+ noun / gerund).
- To give leave to; allow; permit; let; grant.