It is the number seven.
The prefix hepta- means seven.
The combining form hist/o means
Geri- as in geriatry or gero- as in geronotology. From Greek Gero = old man
Xeno- is the combining form meaning strange or other.
Combining form derm/o means: skin
The combining form that means "nail" is onych/o.
Chiro is from the Greek word chiro- χειρο- "hand-"
Combining form for shape
A hump is not a medical term, so I can't give you the correct combining form.
The combining form that means hidden is "crypt-" as in "cryptic" or "cryptology."
The medical terminology combining form for "rapid" is "tachy-." For instance, tachycardia is abnormally rapid heartrate.
The combining word is sphygum