too soon

Short definition from Wiktionary

Adverb

1. 1
   Used other than figuratively or idiomatically: see too, soon.
2. 2
   In a taboo or otherwise inappropriate manner due to timing; inappropriately related to a tragic or unpleasant recent event.

Interjection

1. 1
   Calling out that something is too soon, often in response to someone saying such a joke.