壓線

pressure crease / fig. to toil for sb else's benefit / line ball (i.e. on the line)

to press / to push down / to keep under (control) / pressure

see 壓根兒|压根儿[ya4 gen1 r5]

thread / string / wire / line / CL:條|条[tiao2],股[gu3],根[gen1] / (after a number) tier (unofficial ranking of a Chinese city)