BACTRIAN : a two-humped camel.
Well, darling, the word you're looking for is "separated." It fits all your criteria like a glove. Now go impress someone with your word knowledge, you sly fox.
== ==
I assume that a letter may occur more than once. There are 6 letters in the word 'Marble.' The first letter 'must' be M. The second letter may be chosen in 6 ways. The third, fourth, fifth and the sixth may be chosen in 6 ways. There are 6 to the power 5 = 7,776 words. If the letters cannot repeat: The first letter is always 'M.' The second letter may be chosen in 5 ways. The third in four ways, the fourth in 3 ways, the fifth is 2 ways and the sixth in 1 way. 5x4x3x2x1 = 120 words with first letter M.
Ratio
"arear"
Some six letter words with the fifth letter L are:ampuleargyleawhilebeholdbottlebubblecattlecirclecoupledangledociledwindleeasilyembalmexhalefeeblefemalefiddleheraldinsultlovelymuddleoccultrashlyresultrevoltribaldtumultunfoldvastly
cupful
Some five letter words with second letter U and fifth letter T are:auditbuiltburntburstcubitduvetguestguiltoughtquartquestquiltquintwurst
delta
alohasclavaeclavalclimaxclinalclonalelijahfloraefloralflorasflymanflywayglobalglomalglycanllamasplagalplanarplazaspleiadplicaeplicalpluralsloganslovak
private
figures
badgebargecablecanoecarvedanceeaglefalsegaugehastelargemaizenaivepasterangesaucetablevaluewaste
the six letter word with e as second letter and 5th is... SECRET jestermeltedbeltedtendertendedmendeddealerheaderLentensedges
the word you are looking for is "sexual" <3
equine
multi, mufti, quasi