...that sounds like indivisible but the meaning is more like untaintable?

Its bugging me now.

not very good with stuff like this but what about indubitable or indomitable?

edit, yes i got those with googles help.

Inconceivable?

Nope, none of those chaps.

The only other thing I can think is its a word often used to describe love.

immutable?

Indelible?

Indelible could be it.

Indelible

From open-dictionary.com - the free dictionary.

(a.) That can not be removed, washed away, blotted out, or effaced; incapable of being canceled, lost, or forgotten; as, indelible characters; an indelible stain; an indelible impression on the memory. (a.) That can not be annulled; indestructible.

Or maybe you bought a sandwich from a deli and it tasted off.

Infeasible?

Indefatigable?
For the numpties:

Quote"indefatigable: tireless, unflagging, unwearying (showing sustained enthusiastic action with unflagging vitality) "an indefatigable advocate of equal rights"; "a tireless worker"; "unflagging pursuit of excellence" "

Amazingly youve all come up with great suggestions, but none of those are the word Im after! Unless Im inventing things in my mind again and this word doesnt actually exist.

you say it means something similar to untaintable, but could you give us some more words that are similar in meaning (thesaurus.com doesnt recognise untaintable) Ok, we know that untaintable = something which cannot be tainted, but other words might give us new angles to try...

Quote from: Clockd 0NeNope, none of those chaps.

The only other thing I can think is its a word often used to describe love.

Infactuated ?

infatuated but that doesnt sound anything like indivisible.