watchful

Watchful is a synonym of alert.

As adjectives the difference between alert and watchful

is that alert is attentive; awake; on guard while watchful is observant, vigilant and aware.

As a noun alert

is an alarm.

As a verb alert

is to give warning to.

As a proper noun Alert

is the northernmost inhabited place in Nunavut, Canada.

Oservant is likely misspelled.

Oservant has no English definition.

As an adjective watchful is

observant, vigilant and aware.

As adjectives the difference between watchful and wareful

is that watchful is observant, vigilant and aware while wareful is wary; watchful; cautious.

As adjectives the difference between watchful and guardful

is that watchful is observant, vigilant and aware while guardful is (obsolete|or|poetic) cautious; wary; watchful.

As an adjective watchful

is observant, vigilant and aware.

As an adverb watchingly is

while watching; with watchful attention.

As adjectives the difference between watchful and unwatchful

is that watchful is observant, vigilant and aware while unwatchful is not watchful.

As adjectives the difference between watchful and surveillant

is that watchful is observant, vigilant and aware while surveillant is overseeing; watchful.

As a noun surveillant is

one who watches over another; an overseer; a spy; a supervisor.