in other words; what I (you, etc.) mean is

to startle; to surprise; to astonish

(chiefly in the negative) so much; so often; so long; particularly; especially

Used when something comes to mind: to recall / Used to express agreement: yeah, of course

meaningless

nonsense / meaninglessness

profound, deeply meaningful

everything

semantics (as a field of study), semasiology

(colloquial) Clipping of 意味深長 (imishinchō).