Doubts about whether to write words separately or together in German are frequently grammatical in nature. Here various combinations are discussed (noun-verb combinations, adjective-verb combinations, various combinations with adjectives and participles) to establish whether the examples in question are complex words or syntagmas. In the process, criteria are identified for words and non-words (syntagmas) and drawn upon to propose rules for writing words separately or together. At the same time it leaves a degree of latitude, as tolerance in doubtful cases is appropriate to the system.