spine

[1]	backbone , spinal column , vertebral column , spinal column , vertebrae , backbone , back , rachis
[2]	spur , thorn , needle , acantha , barb , spike , spur , prong , quill , ray , barbel , bristle , prickle , (Technical) barbule , spicule/spiculum/spiculadecrease , diminish , reduce
[3]	step in , thorn , prickle , intervene , interfere , pricker , sticker , intercede , become involved , spikelet
[4]	backbone , step on it , hurry (up) , make haste , hasten , speed up
[5]	step out , go outside/out of doors , leavego out , socializebecome disinvolved , withdraw , secede
[6]	step up , improve , progressincrease , accelerate , raise , intensify , boost , escalate , up , speed up