He who is the source of supreme bliss, joy-personified, the very manifestation of happiness. He, who bestows joy and happiness on all those who approach him
The etymology of the word Śambhuḥ comes from the ‘sandhi’ (coming together) of two words: Śam which means happiness or bliss-supreme (ānanda) and bhuḥ meaning “source-of” or ’emanating from’
It is interesting to note that Śambhu is one of the names of Śiva and refers to that ‘one’ who holds Gaṅgā within the folds of his hair-locks and sports the crescent moon on his forehead. Three-eyed, he is always joyful. In his hand, he holds the trident. He is as pure and white as camphor and his body is entirely dusted with the ash . And it is Śiva who is cidānanda-swarupā (चिदानन्द स्वरूप) – bliss, unqualified natural state of tranquility/happiness.
This is the third instance during the first set of 38 ‘beads’ where the name refers to an aspect of Śiva – again highlighting the complete abheda‘ (non-difference) between Śiva and Viṣṇu
Further, in the Rāmāyaṇa, there are several instances where Rāmā is referred to as one with such a pleasing personality that he was source of joy to everyone who came in contact with him (even many of his enemies).
In Sadasiva Brahmendra‘s celebrated Ātma-Vidya-Vilāsa, he talks about “that bliss” that the ātmān living (Vilāsa) in the bliss of its own knowledge (Ātma-Vidya) enjoys. It is a poem of 62 stanzas – in stanza 14 he talks about that pure bliss of the person who has understood his/her own ‘self’
त्वमहमभिमानहीनो मोदितनानाजनाचारः ।
विहरति बालवदेको विमलसुखाम्भोनिधौ मग्नः ॥ १४॥ 
Completely devoid of any conceit or any identification with one’s ego or any distinction in the nature of “I” and ‘You’ he (the jivanmukta) frolics and sports alone, like a child – happily accepting the behavior of people – undeterred by anything they say or do to him… for he, immersed in the ocean of pure bliss (that is his own self. 
Too often, we try to locate our happiness in things that are external, outside of us – in people and their acceptance or rejection of us, in material things, in ephemeral moments of joy – while all of this is temporary and short-lasting…
This name Śambhuḥ tells us that true happiness that is everlasting lies within, in the cave of our own hearts. It is in finding this ‘center’, holding on to it and expanding it that we find ‘ourselves’ and the inexhaustible treasure of bliss within – A Sri Aurobindo says it is about “Living Within and Growing Within”