As nouns the difference between lyricism and poeticism
is that lyricism is great enthusiasm while poeticism is (uncountable) poetic style; lyricism.
lyricism
English
Noun
(-)
Great enthusiasm.
Suitability to be sung or used as lyrics.
poeticism
English
Noun
(uncountable) Poetic style; lyricism.
(countable) A poetic phrase, utterance, etc.