delay,
retard,
slow,
slacken,
detain mean to cause to be late or behind in movement or progress.
delay implies a holding back, usually by interference, from completion or arrival.
bad weather delayed our arrivalretard suggests reduction of speed without actual stopping.
language barriers retarded their progressslow and
slacken also imply a reduction of speed,
slow often suggesting deliberate intention
medication slowed the patient's heart rate,
slacken an easing up or relaxing of power or effort.
on hot days runners slacken their pacedetain implies a holding back beyond a reasonable or appointed time.
unexpected business had detained her