Ahem and Alas

Ahem noun - The utterance of a sound similar to clearing the throat; intended to get attention, express hesitancy, fill a pause, hide embarrassment, warn a friend, etc..

Alas and ahem are semantically related in emphatic exclamation topic. In some cases you can use "Alas" instead a noun "Ahem".

Alas adverb - By bad luck.

Ahem and alas are semantically related in boo topic. You can use "Ahem" instead a noun "Alas", if it concerns topics such as wow.