What suffix turns abstract into it noun?

There is no standard suffix that makes a Word an abstract noun. An abstract noun is determined by the meaning of the noun or the use of the noun.

An abstract noun is a Word for things that your five senses cannot detect. You can't see them, hear them, smell them, taste them, or touch them. They are Words for things that you know, learn, think, understand, or feel emotionally.

An example list of abstract nouns:

anger

belief

courage

democracy

efficiency

fun

generosity

hate

imagination

judgement

keepsake

legend

mystery

nature

organization

pride

quiet

romance

strategy

trust

valor

wish

excitement

year

zeal