hinderer
hin·der 1
H0208100 (hĭn′dər)These verbs mean to slow or prevent progress or movement. To hinder is to hold back or delay, as by barring the way forward: The unfair performance review threatened to hinder her career.
Hamper suggests the imposition of restrictions or limitations: "He was a little hard of hearing; it hampered him in learning" (Oliver La Farge).
To impede is to slow by making action or movement difficult: "[The] wagon proceeded down the street at a slow walk, impeded by the crush of curiosity seekers" (Stephen O'Connor).
Obstruct implies the presence of obstacles: Passage of the bill was obstructed by a filibuster.
To encumber is to weigh down, as with complications or difficulties: "[King] Leopold particularly envied the Hapsburgs because, unlike him, they were little encumbered by parliaments and constitutions" (Adam Hochschild).