Fornander gives three meanings:

1. Awa, s. Haw., harbour, cove, creek, channel; awaa, to dig as a pit, a ditch; awawa, a valley, space between two prominences, space between the fingers and toes. Tah., ava, a harbour, channel. Sam., ava, a boat-passage, opening in the reef, anchorage; v. to be open, as a doorway. Marqu., ava, interval, passage. The Malgasse ava, a rainbow, may refer to this family, in the sense of an arch, a bay, a hollow, curved space on the firmanent. Sanskr., avaţa, a pit; avata, a well; avatas, below, in the lower regions; ava-kâça, space, interval; avama, low, opp. to high, probably all referring themselves to ava, prep. with the primary sense of 'down, below, away, off', as its derivatives plainly indicate.

2. Awa, s. Haw., fine rain, mist. Tong., Sam., afa, storm, hurricane; afu, a waterfall. N. Zeal., awa, a river. Fiji., cava, a storm. Mal., awap, mist, dew. Sangvir Island, sawan, a river. Rotti, Ofa, id. Tagal., abo-abo, rain. Malg., sav, mist, fog. Sanskr., ap, apas, water. Lat., aqua; Romain, ava, water, rain-water. Goth., ahwa; O. H. Germ., ouwa, water. Germ., aue, au, brook. Swed., å, id. Irish, abh, water; abhan, river. Welsh, aw, fluid. Pers., âw, âb, water. A. Pictet ... refers the Celtic and Persian forms to a Sanskrit root av, 'ire', whence avana, rapidity, avani, river; and he refers the Latin and Gothic forms to a Sanskrit root aç or ak, 'permeare, occupare', from which spring a number of derivatives expressive of 'le mouvement rapide, la force pénétrante' ... In view of the Polynesian forms, Haw., Sam., Tagal., and their meanings, I prefer to follow Benfey and Bopp in referring the West Aryan as well as the Polynesian forms to the Sanskrit ap, whether that be the original form itself or a contracted modification of it. It seems to me to have been in the very nature of language that men in the olden times should have commenced by giving distinct and instantaneous names to objects around them, and to natural phenomena, before they invested those objects with names derived by after-thought and reflection from this or that quality characteristic of those objects. Many, if not most, of such original names were doubtless lost in the course of ages, and supplanted by synonyms derived from and expressive of some quality or other in the objects named; but many still survive to baffle the analysis of philologists, and to assert their claims to priority over synonyms that must necessarily have been of later formation. 

3. Awa, s. Haw., Sam., Tah., name of a plant of a bitter taste, but highly relished throughout Polynesia - 'Piper Methysticum' - from which an intoxicating drink is made; the name of the liquor itself. Tong., N. Zeal., Rarot., Marqu., kawa, id. Haw., awa-awa, bitter. Sam., a'awa, id. Tong., N. Zeal., kakawa , sweet. Sanskr., av, to please, satisfy, desire (Benfey); ava, nourishment (Pictet). Pers., âwâ, nourishment; abâ, bread. Lat., aveo, crave after, long for; avena, oats. See au 1.