Final answer:
The poem 'Psalm of Life' by Henry Wadsworth Longfellow has an optimistic attitude towards life, encouraging living with purpose and hope.
Step-by-step explanation:
The word that best describes the attitude toward life expressed in the poem 'Psalm of Life' is optimistic. The poem, written by Henry Wadsworth Longfellow, implores readers to live life to the fullest and act with purpose. Its central theme is to be courageous and strive forward, despite life's challenges. Hope and determination permeate each stanza, as Longfellow encourages us not to waste the precious time that we have. The poem is an invocation to embrace life with all its potential and to reject the notion that life is an empty dream.