decrease, diminish, lessen, fall - decrease in size, extent, or range; "The amount of homework decreased towards the end of the semester"; "The cabin pressure fell dramatically"; "her weight fall to under a hundred pounds"; "his voice fell to a whisper"

slow up, slow, slow down - cause to proceed more slowly; "The illness slowed him down"

delay, detain, hold up - cause to be slowed down or delayed; "Traffic was delayed by the bad weather"; "she delayed the work that she didn't want to perform"

weaken - become weaker; "The prisoner's resistance weakened after seven days"

bog, bog down - cause to slow down or get stuck; "The vote would bog down the house"

decelerate, slow, slow down, slow up, retard - lose velocity; move more slowly; "The car decelerated"

constipate, clog - impede with a clog or as if with a clog; "The market is being clogged by these operations"; "My mind is constipated today"

modify, qualify - add a modifier to a constituent

moderate - make less fast or intense; "moderate your speed"

retard - cause to move more slowly or operate at a slower rate; "This drug will retard your heart rate"

fishtail - slow down by moving the tail sideways; "The airplane fishtailed on the runway"

vege out, vegetate - engage in passive relaxation; "After a hard day's work, I vegetate in front of the television"

sit back, take it easy - settle into a comfortable sitting position

change state, turn - undergo a transformation or a change of position or action; "We turned from Socialism to Capitalism"; "The people turned against the President when he stole the election"