Here are a few possibilities:
If "slink" means "to move in a stealthy or cowardly way":
* Stroll: To walk leisurely and confidently.
* Strut: To walk with a proud and confident gait.
* March: To walk with a firm and purposeful stride.
If "slink" means "to move or go away secretly or shamefully":
* Parade: To walk or march in a public procession, often with pride.
* Strut: To walk with a proud and confident gait, often to attract attention.
* Stand tall: To hold oneself upright and with confidence.
If "slink" means "to shrink back or away from something":
* Embrace: To welcome or accept something eagerly.
* Advance: To move forward or make progress.
* Stand firm: To resist pressure and remain steadfast.
The best opposite word for "slink" will depend on the specific context and the nuance you wish to convey.