The second part of the verse is this:
אֶרֶךְ אַפַּיִם, וּגְדָל-חָסֶד.
EH-rekh ah-paYEEM oog'DAHL-CHAHsehd
אֶרֶךְ EH-rech= is a masculine noun meaning "length" or "delay". It is related to the verb: ah-RAKH "to stretch, to be long, to wear on"
It is paired with the word
אַפַּיִם=ah-paYEEM, which is plural form of אף, which literally means "nose", but is often used in Hebrew to denote "anger, wrath". It comes from the word אנף "to breathe heavily, to be angry". אף can also refer to "the nostrils, face". The picture I get here is that when one is angry, the nostrils flare and one breathes heavily.If you would like to explore this very common Hebrew expression, click this link: http://biblesuite.com/hebrew/639.htm
The point is that HaShem delays His anger, or is slow to anger!
gaDOHL means "great, large, tall, high, mighty, old, elder". Note that the vav prefix, meaning "and" is lengthened from "veh" in pronunciation to "OO". This is done before certain letters or vowels. Here, it is because of the sheva under the gimel. (hhhmmm, that would be another blog entry).
חסד, CHEsed, we have seen before. Here the vowels are lengthened due to the makkef joining so that the emphasis stays with the chet. "love, kindness, benevolence, good-will, favour, benefit, mercy, grace, piety"
Together, the two words could be translated: "And great of benevolence"
So the entire eighth verse of Psalm 145:
חַנּוּן וְרַחוּם יְהוָה; אֶרֶךְ אַפַּיִם, וּגְדָל-חָסֶד.
"Gracious and merciful is HaShem; (he) delays anger and (is) great of benevolence"
Feel free to send questions or comments!