Obstructionist (noun)

1. A person who deliberately obstructs or hinders progress or action, especially in a political context.
2. A person who resists change or progress by opposing or blocking proposed initiatives or reforms.

Origin:

Late 19th century, from obstruction + -ist, a suffix indicating a person.

Examples:

1. The obstructionist was accused of sabotaging the legislative process.
2. The obstructionist was seen as a major roadblock to progress.
3. The obstructionist was a thorn in the side of the majority party.
4. The obstructionist was a vocal opponent of the government's reforms.
5. The obstructionist was criticized for being more interested in politics than policy.