First of all - I was replying to OP who was talking about such. Not you.
Second, search engines do have a localization aspect - if Bimbo isn't an amply-used word in your region, it's going to give results you may not be looking for. You would use terms with higher recognition in your region. That goes to why you might have even odder results for the word bimbo than if you did live in North America.
Third, as for your "Big tits bimbo" claim - "big tits" is more likely to be used for porn. Bimbo has several connotations, including the bakery and a non-porn fashion style and life-style. Also, bimbo is used in other less adult website - which, yes, search engines include in the algorithms to determine result hierarchy, including link-backs, references, site's longevity, etc. So searching for big tits is a lot more likely to bring up porn sites as a higher search result than big tits bimbo. Big tits bimbo may be obvious for your use, but it's not necessarily so for larger populations of groups.
Finally, instead of using bimbo, searching using better descriptors would return more specific results for that the person searching is looking for. Search big tit porn. Search blonde big tits. Search dumb blonde big tit porn. Slang can create odd search results.
But the bottom line of this all is: No, major search engines do not censor the word bimbo.