To the chief Musician
natsach  (naw-tsakh')
to glitter from afar, i.e. to be eminent (as a superintendent, especially of the Temple services and its music)
A Psalm
mizmowr  (miz-more')
instrumental music; by implication, a poem set to notes -- psalm.
of David
David  (daw-veed')
loving; David, the youngest son of Jesse -- David.
when Nathan
Nathan  (naw-thawn')
given; Nathan, the name of five Israelites -- Nathan.
the prophet
nabiy'  (naw-bee')
a prophet or (generally) inspired man -- prophecy, that prophesy, prophet.
bow'  (bo)
to go or come (in a wide variety of applications)
unto him after he had gone in
bow'  (bo)
to go or come (in a wide variety of applications)
to Bathsheba
Bath-Sheba`  (bath-sheh'-bah)
daughter of an oath; Bath-Sheba, the mother of Solomon -- Bath-sheba.
Have mercy
chanan  (khaw-nan')
to bend or stoop in kindness to an inferior; to favor, bestow; causatively to implore (i.e. move to favor by petition)
upon me O God
'elohiym  (el-o-heem')
angels, exceeding, God (gods)(-dess, -ly), (very) great, judges, mighty.
according to thy lovingkindness
checed  (kheh'-sed)
kindness; by implication (towards God) piety: rarely (by opposition) reproof, or (subject.) beauty
according unto the multitude
rob  (robe)
abundance (in any respect) -- abundance(-antly), all, common (sort), excellent, great(-ly, -ness, number), huge, be increased, long, many, more in number, most, much, multitude, plenty(-ifully), very (age).
of thy tender mercies
racham  (rakh'-am)
compassion (in the plural); by extension, the womb (as cherishing the fetus); by implication, a maiden
blot out
machah  (maw-khaw')
to stroke or rub; by implication, to erase; also to smooth (as if with oil), i.e. grease or make fat; also to touch, i.e. reach to
my transgressions
pesha`  (peh'-shah)
a revolt (national, moral or religious) -- rebellion, sin, transgression, trespass.