(a.) Descending gradually; moderately steep; sloping; downhill.

abjuration abjurement abnegation aging chucking chucking out collapsing coming apart contempt contractive contradiction cracking crumbling decadent deciduous declension declination declinature declined declivate declivitous declivous decreasing decrescendo decrescent decurrent degenerate deliquescent denial deprivation descendant descending despisal despising deteriorating diminishing diminuendo dipping disagreement disallowance disapproval discard disclaimer disclamation discounting disintegrating dismissal disobedience disownment disregard dissent doting down down-reaching downcoming downfalling downgoing downgrade downhill downsinking downward draining drooping dropping dwindling dying ebbing effete exception exclusion fading failing falling flagging fragmenting getting on going to pieces growing old holding back ignoring languishing lessening marcescent nay negation negative negative answer nix no nonacceptance nonapproval noncompliance nonconsent nonconsideration nonobservance on the descendant on the downgrade on the wane passing by pining plummeting plunging putting away putting out rebuff recantation receding reductive refusal regressive rejection renouncement repudiation repulse retention retiring retreating retrograde retrogressive sagging scouting senescent setting shrinking shriveling sinking sliding slipping slumping spurning submerging subsiding tabetic throwing out thumbs-down tottering tumbledown turndown turning out unwillingness waning wasting wilting withering withholding worsening