There are several words that can be used as synonyms for the phrase "coming without previous intimation." The first word that comes to mind is "unexpectedly," which means something that was not anticipated or foreseen. Another synonym for this phrase is "unannounced," which means that there was no prior announcement or notice given about the sudden appearance of something or someone. Similarly, the words "surprise" and "sudden" can also be used to describe the unexpected nature of something or someone arriving without prior warning. Another word that is often used as a synonym is "abruptly," which suggests something happening suddenly and without warning.