Synonyms for Slightly:

adv.

a little (adverb)
lightly, imperceptibly, scarcely any, insignificantly, Inconsiderably, hardly at all, to some extent, inappreciably, hardly noticeable, somewhat.
all (adverb)
somewhat.
compactly (adverb)
modestly, deficiently, shortly, scantily, niggardly, miserly, compactly, minimally, punily, meagerly, stingily, triflingly, parsimoniously, slimly, delicately, sparingly, minutely, negligibly, Paltrily.
lightly (adverb)
lightly.

adv

compactly (adverb)
modestly, deficiently, shortly, scantily, niggardly, miserly, compactly, minimally, punily, meagerly, stingily, triflingly, parsimoniously, slimly, delicately, sparingly, minutely, negligibly, Paltrily.
lightly (adverb)
sparingly.
moderately (adverb)
a little.
rather (adverb)
a bit, to some extent.
somewhat (adverb)
insignificantly.

n.

a little (noun)
unimportantly, imperceptibly, ever so little, lightly, scarcely any, hardly noticeable, inappreciably, hardly at all, rather on a small scale, insignificantly, to a small extent, to some extent, Inconsiderably.
slightly (noun)
slimly, somewhat, slenderly.

Other synonyms:

partly. mildly. vaguely. somewhat
somewhat.