[合「あ」]う => To do A together/mutually N4
Secondary Verb
も[同然「どうぜん」]だ => The same as saying A, as good as A N2
Adjectival, Descriptions
へ => Go to N, head to N , Often followed by verbs like 行く/いく, 来る/くる, 向かう/むかう… N5
Particles