Acted sycophantically (6)
I believe the answer is:
fawned
(Other definitions for fawned that I've seen before include "Behaved over-humbly to gain favour" , "Tried to win favour by obsequious behaviour" , "Courted favour by cringing flattery" , "Behaved obsequiously - like young deer?" , "Tried to gain favour by flattering" .)