lose ground (?.)
- arrest
- backpedal
- backslide
- backwater
- be found wanting
- brake
- check
- clip the wings
- cock
- collapse
- come short
- curb
- decelerate
- decline
- delay
- detain
- draw rein
- ease off
- ease up
- fail
- fall astern
- fall away
- fall behind
- fall short
- get behind
- go backwards
- go behind
- hold back
- hold in check
- hold up
- impede
- jerk back
- keep back
- lack
- lag
- lapse
- let down
- let up
- lose momentum
- lose speed
- moderate
- not answer
- not hack it
- not make it
- not make out
- not measure up
- not stretch
- not suffice
- obstruct
- pull back
- recede
- recidivate
- reef
- regress
- rein in
- relapse
- relax
- retard
- retrocede
- retroflex
- retrograde
- retrogress
- return
- revert
- run short
- set back
- slack off
- slack up
- slacken
- slip back
- slow
- slow down
- slow up
- slump
- stay
- stop short
- take in sail
- throttle down
- want
