I am looking for a way to emphasise words to put emphasis on words, actions, or people similar to the British English word bloody:
This man is a bloody thief!
Dieser Mann ist ein [?] Dieb!
I am looking for a way to emphasise words to put emphasis on words, actions, or people similar to the British English word bloody:
This man is a bloody thief!
Dieser Mann ist ein [?] Dieb!
You might form the compound with Scheiß-, hence Scheißdieb (which, beware, means shitty). Or adjectivation, as alredy pointed out, with verdammt.
Riesen- often works, but not always. You can't say Riesen-Dieb, but Riesen-Arschloch (=big ashole), Riesen-Depp (=big idiot) or Riesen-Sache (=big deal) are common.
Verdammter Dieb, verdammtes Arschloch and verdammter Depp would work, too. But it's uncommon to say eine verdammte Sache. You would say instead eine verdammt große Sache or eine verdammt komplizierte Sache.
The best answer depends a bit on the use case.
If you’re learning German and need a way to express intensity in a (mildly) foul way, I’d suggest to adopt the prefix Scheiß- lit. ‘shit, shitty’ – which may also mean ‘bad’ – for where you‘d say bloody in British or fucking in American English. (I don’t know what Canadians, Australians, Indians etc. would use.) Note that all lexemes are somewhat related to bodily functions. I believe there is no blood-based swearword in German, by the way, whereas fucking now has a more literal cognate, verfickt. If you’d like to repeat the root for rhetoric effect, as in fucking motherfucker or alliterative fucking fuck-face, you may combine Scheiß- (also stand-alone as der Scheiß or die Scheiße) with the adjective beschissen, e.g. beschissener Scheißkerl ‘shitty shithead’ or, mixing in another word for excrements, beschissene Kackscheiße ‘shitty shit shite’.
Dieser Mann ist ein Scheißdieb.
Dieser Mann ist ein Kackdieb.
Dieser Mann ist ein beschissener Dieb.
If you‘re translating a text from English to German, verdammt ‘condemned, doomed, cursed’ may be a better choice, not least because it’s an adjective with two syllables, too (unless inflected). Unlike the words discussed above, it has its roots in religion (not necessarily Christianity) and may be boosted by gott- (and more in dialects). There are some standing expression like verdammt noch mal / verdammt noch eins, verdammter Mist, verdammte Axt.
Dieser Mann ist ein verdammter Dieb.
Dieser Mann ist ein gottverdammter Dieb.
There are more prefixes that may be used as intensifier, but are not as generally applicable, e.g. Super- or – to also get animal-based curses in here – Sau-, which incidentally both don’t work with the example, although I cannot tell exactly why (maybe because it could translate to ‘master thief’ and ‘pig thief’ respectively). The former, like similar Ober- (not Über-!), works best with insults, as in Superarschloch, the latter works well with adjectives, e.g. saugut ‘super good’.
Dieser Mann ist ein *Superdieb.
Dieser Mann ist ein *Saudieb.
In many cases, though, there are also more specialized, established expressions of adjective plus noun or just a compound noun.
Dieser Mann ist ein elender Dieb. – ‘miserable’
Dieser Mann ist ein räudiger Dieb. – from räudiger Hund/Köter/… ‘mangy dog’
Dieser Mann ist ein gemeiner Dieb. – means both ‘common’ (oldish) and ‘mean’, may be prefixed by hunds- ‘doggish’
Dieser Mann ist ein übler Dieb. – ‘awful’, may become übelst as an adverb
dreckiger would probably work fine, too.