suggestion A2

/sə(ɡ)ˈd͡ʒɛs.t͡ʃən/ An idea or plan put forward for others to consider.

insubstantial C2+

/ˌɪnsəbˈstænʃəl/ lacking substance, strength, or reality; flimsy

insufferable C2+

/ɪnˈsʌfərəbəl/ too unpleasant or arrogant to be endured