THOU: informal use of the second person singular, opposed to 'you', the formal version. Nominative case, used as the subject of the sentence. In use until the XVIIIth century. Same division as the Spanish forms tú (thou), usted (you).
ART:
second person singular of the verb 'to be'. Present English 'are'.
HATH: third person singular of the verb 'to have'. Present English 'has'.
DIMM(E)D: apocopated form of the regular past participle.
UNTRIMM(E)D: apocopated form of regular the past participle.
OWEST: the suffix '-est' indicated the second person singular in Modern English. Now lost in contemporary English.
WANDER(E)ST: apocopated form of the suffix '-est' (second person singular marker).
GROWEST: the suffix '-est' indicated the second person singular in Modern English. Now lost in contemporary English.
APOCOPATED FORM: poetic licence consisting in the elision of a certain sound in a word in order to shorten the number of syllables in the line of verse; thus, the prosodic composition of the line will fit a specific pattern. This feature is signal by putting an apostrophe (') in the place of the elided sound.
DIMM(E)D: the past participle, unlike contemporary pronunciation (one syllable [dimd]) would comprise two syllables 'dim-med [dimid]'.
UNTRIMM(E)D: the past participle, unlike contemporary pronunciation (two syllables [^ntrimd]) would comprise three syllables 'un-trim-med [^ntrimid]'.
WANDER(E)ST
common pronunciation would comprise three syllables 'wand-er-est'. In apocpated
form, only two 'wand-erst'.