偏劳

偏劳	piān láo	undue trouble / Thank you for having gone out of your way to help me.
偏	piān	to lean / to slant / oblique / prejudiced / to deviate from average / to stray from the intended line / stubbornly / contrary to expectations
劳	láo	(bound form) to toil; labor / (bound form) laborer / (bound form) meritorious deed / (bound form) fatigue / to put sb to the trouble (of doing sth) / to express one's appreciation (Taiwan pr. [lao4])