the quality or condition of being intense.

great energy, strength, concentration, vehemence, etc., as of activity, thought, or feeling

He went at the job with great intensity.

a high or extreme degree, as of cold or heat.

the degree or extent to which something is intense.

a high degree of emotional excitement; depth of feeling

The poem lacked intensity and left me unmoved.

the strength or sharpness of a color due esp. to its degree of freedom from admixture with its complementary color.

Physics . magnitude, as of energy or a force per unit of area, volume, time, etc.

Speech .

the correlate of physical energy and the degree of loudness of a speech sound.

the relative carrying power of vocal utterance.

noun

apathy , dullness , inactivity , laziness , lethargy , moderation

noun

acuteness , anxiety , ardor , concentration , deepness , depth , earnestness , emotion , emphasis , energy , excess , excitement , extreme , extremity , fanaticism , ferment , ferociousness , ferocity , fervency , fervor , fierceness , fire , force , forcefulness , fury , high pitch , intenseness , keenness , magnitude , might , nervousness , potency , power , severity , sharpness , strain , strength , tenseness , tension , vehemence , vigor , violence , volume , weightiness , wildness , pitch , vehemency , passion , zeal